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browsercc

Compile C/C++ programs in your browser to WebAssembly.

This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.

While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.

Usage

The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.

browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:

typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;

Package contents

We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):

  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.

Example

The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs. To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.

The bare minimum to compile and run a C++ program is:

import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"

About

Compile C/C++ programs in your browser to WebAssembly

danielbertalan.dev/browsercc/

Topics

browserclangcompilercplusplusonline-compilerwasm

Resources

Readme
MIT license
Activity

Stars

6 stars

Watchers

1 watching

Forks

2 forks
Report repository

Releases

Packages

Used by

Contributors

Languages

, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
BranchesTags
Repository files navigation
browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
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Readme
MIT license
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1 watching
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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browsercc
Compile C/C++ programs in your browser to WebAssembly.
This repository contains build scripts for compiling a Clang/LLVM toolchain to WebAssembly, which can be used to compile C/C++ programs right in the browser. The compiler creates WebAssembly binaries that use the standard WASI system interface and can be executed by a simple runtime like @bjorn3/browser_wasi_shim.
While WASI lacks some features like C++ exceptions and threading support, it requires much less build infrastructure (no Python, shell scripts, etc.) and JavaScript glue code than Emscripten. If you need Emscripten's more advanced features, check out emception.
Usage
The NPM release of browsercc contains a precompiled toolchain, but you can also build it yourself with npm run build. This uses Docker to create a Linux container with the necessary dependencies, and then calls build.sh to compile the toolchain.
browsercc provides a JavaScript function for compiling source code given as a string to a WebAssembly module:
typeCompilationJob={source: string;fileName: string;flags: string[];extraFiles?: {[fileName: string]: string|ArrayBuffer;};};typeCompilationResult={compileOutput: string;module: WebAssembly.Module|null;};asyncfunctioncompile(_: CompilationJob): Promise<CompilationResult>;
Package contents
We try to optimize the artifact size as much as possible (except LTO, blocked on llvm/llvm-project#136197), but LLVM is a huge project regardless. The following files are included in the NPM package (uncompressed sizes):
  • index.js (~5 kB unminified): The main JavaScript file that contains the compile function.
  • clang.js, lld.js (70 kB unminified each): The Emscripten glue code for the Clang and LLD binaries.
  • clang.wasm (43 MB): The main compiler binary.
  • lld.wasm (23 MB): The linker binary (includes the LLVM backend because of LTO support, could be made smaller).
  • sysroot.tar (29 MB): C and C++ standard libraries and their headers.
  • stdc++.h.pch (19 MB): Precompiled header for speeding up C++ STL usage. Only downloaded if getPrecompiledHeader() is used.
Example
The index.html file contains a simple Compiler Explorer-like interface for compiling C/C++ programs.
To run it, execute npm run demo and open the link printed in the console. If you open the localhost link, it will use your local build, otherwise it will load the pre-built NPM package from a CDN.
The bare minimum to compile and run a C++ program is:
import{compile}from"browsercc";import{WASI,File,OpenFile,ConsoleStdout}from"@bjorn3/browser_wasi_shim";const{ module, compileOutput }=awaitcompile({source: `#include <iostream>#include <string>int main() { std::string name; std::cin >> name; std::cout << "Hello, " << name << "!" << std::endl; return 0;}`,fileName: "main.cpp",flags: ["-std=c++20"],});// Set up stdin to contain the string "browsercc\n" and capture stdout/stderr in the `output` variable.conststdin=newTextEncoder().encode("browsercc\n");letoutput="";constfds=[newOpenFile(newFile(stdin)),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),newConsoleStdout((data: Uint8Array)=>{output+=newTextDecoder().decode(data);}),];constwasi=newWASI([],[],fds);constinstance=awaitWebAssembly.instantiate(module,{wasi_snapshot_preview1: wasi.wasiImport,});wasi.start(instance);console.log(output);// "Hello, browsercc!"
About
Compile C/C++ programs in your browser to WebAssembly
danielbertalan.dev/browsercc/
Topics
browserclangcompilercplusplusonline-compilerwasm
Resources
Readme
MIT license
Activity
Stars
6 stars
Watchers
1 watching
Forks
2 forks
Report repository
Releases
Packages
Used by
Contributors
Languages