Decompile and extract Microsoft Compiled HTML Help (.chm) manuals, ebooks, and developer documentation into standard HTML and images directly in your browser without Windows or third-party desktop tools.
Detailed side-by-side format architecture for CHM Document (.chm) and ZIP Document (.zip). Every conversion executes strictly within isolated browser memory without network transit.
Drag and drop your .chm file onto the working surface or use the system file dialog. File magic bytes are verified locally on device.
Select a quality preset (Lossless, Visually Lossless, Balanced, Smallest) or adjust advanced encoding switches in the options panel.
Click CONVERT to execute local WebAssembly compilation. Save the finished .zip directly to local storage, or stage it for chaining.
Prefer local shell scripting? Run this standard POSIX command on your machine to achieve equivalent transcoding without a web interface:
# Convert CHM to ZIP locally
pandoc input.chm -o output.zipWorking with files across multiple web pages? The official convrtr Chrome Extension adds native Side Panel docking, right-click context menu media extraction, and visible viewport capture. Powered by the same zero-upload client-side WebAssembly engine.
A .chm (Compiled HTML Help) file is a proprietary archive format developed by Microsoft in 1997 based on the Info-Tech Storage Format (ITSF). It was the standard format for Windows software documentation, ebooks, and software SDK references.
Compiled HTML Help relies on Windows-specific ActiveX controls and the Microsoft HTML Help Viewer (hh.exe). Modern macOS, Linux, iOS, and Android systems have no built-in viewer for CHM archives, and Windows 10/11 frequently blocks CHM files downloaded from the internet with security errors.
convrtr extracts all embedded HTML articles, images (.gif, .jpg, .png), CSS stylesheets, and table of contents files (.hhc/.hhk), bundling them into a standard ZIP archive that can be opened in any web browser.
No! All parsing of ITSF headers, directory chunks, and asset extraction occurs 100% locally in your web browser using pure TypeScript and WebAssembly.
Never. All decompression and ZIP bundling occur completely inside your browser's local memory. No files or private technical documents ever leave your computer.
CHM Document (CHM) and ZIP Document (ZIP) serve distinct roles across the digital workflow. Converting to ZIP provides optimized compatibility, modern compression efficiency, or standardized playback across web browsers, operating systems, and media production environments.
The output format (ZIP) is inherently lossless or supports lossless operation. Your original visual or audio fidelity is mathematically preserved without quantization artifacts.
Never. convrtr is architected with a strict zero-upload model. All processing, decoding, decompression, and encoding happen 100% locally on your machine using sandboxed WebAssembly and Web Workers. Your data never touches an external server, database, or analytics collector.
You can execute this conversion locally via command-line utilities such as ffmpeg, cwebp, or ImageMagick. For example: see the developer terminal recipe provided in the technical specifications dossier above. convrtr provides the identical local-first capability directly inside your browser without installing CLI packages.
Yes. You can drop multiple .chm files into the instrument to process them concurrently in browser Web Workers, or click 'Open in Master Studio' to queue mixed formats, configure individual targets, and export as a single ZIP archive.
Inside Microsoft Compiled HTML Help (ITSP/ITIR) format, LZX compression decompression, and how to unpack legacy documentation to modern HTML/ZIP without Internet Explorer.