Which MIME types are related to file extension ".chm"?
The .chm file extension is associated with 2 MIME types:
application/vnd.ms-htmlhelp, chemical/x-chemdraw.
A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.
About .chm Files
CHM files are compiled HTML help files used by Microsoft Windows.
They bundle HTML pages, images, and scripts into one file for offline help or documentation.
The primary MIME type is application/vnd.ms-htmlhelp, which tells the system it is a Windows help file.
- Main Use: Provide help documentation for software.
- Content: Contains formatted text, links, and media for user guidance.
- Software: Opened by Microsoft HTML Help Viewer and other compatible readers.
In rare cases, the MIME type chemical/x-chemdraw also uses the .chm extension.
- Alternate Use: Store chemical structure data created with ChemDraw.
- Data Stored: May include 2D or 3D molecular drawings for chemical analysis.
- Software: Opened by programs like ChemDraw.
Relationship between file extension and MIME type
A file extension is a suffix at the end of a filename that indicates what type of file it is. File extensions help both users and operating systems identify what application should be used to open the file.
File extensions are typically separated from the filename by a period (dot) and consist of 2-4 characters, though they can be longer. For example, in the filename "document.pdf", ".pdf" is the file extension.
File extensions are closely related to MIME types, as they both serve to identify the format of a file. However, while MIME types are used primarily by web browsers and servers, file extensions are used by operating systems and applications.
Associated MIME types
application/vnd.ms-htmlhelp, chemical/x-chemdraw
FAQs
What is a CHM file?
A CHM (Compiled HTML Help) file is a proprietary Microsoft format that compresses a collection of HTML pages, images, and navigation tools into a single file. It is primarily used for software documentation and offline help manuals. Rarely, the extension is used for ChemDraw files containing chemical structures.
How do I open a CHM file on Windows?
Windows has a built-in viewer called the Microsoft HTML Help Executable (hh.exe). You can simply double-click the file to open it. If it does not open, right-click the file, select Open with, and choose the Microsoft HTML Help Executable.
Why is my CHM file opening but showing blank pages?
This is a common security feature in Windows for files downloaded from the internet. To fix it, right-click the CHM file, select Properties, check the Unblock box at the bottom of the General tab, and click Apply.
Can I view CHM files on macOS or Linux?
Yes, but you will need third-party software since the format is native to Windows. Mac users can use apps like Chmox or iChm, while Linux users often rely on xCHM or KchmViewer to render the content.
How do I convert a CHM file to PDF?
You can use eBook management software like Calibre to convert CHM files to PDF, EPUB, or other document formats. There are also various online conversion tools that can extract the HTML content and compile it into a printable PDF.
What is the correct MIME type for CHM files?
For standard Windows help files, the MIME type is application/vnd.ms-htmlhelp. In the specific context of chemical software, it may be chemical/x-chemdraw. For more details on these configurations, visit mime-type.com.
Is it safe to open CHM files?
CHM files can pose a security risk because they support scripting languages like JavaScript and ActiveX controls. Malicious files can execute harmful code, so you should only open CHM files from trusted sources or vendors.
How can I extract the HTML code and images from a CHM file?
Since a CHM file is essentially a compressed archive, you can open it using file compression tools like 7-Zip or WinRAR. This allows you to browse the internal folder structure and extract the source HTML pages and image assets.
General FAQ
What is a MIME type?
A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.
MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.
MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.
How do I find the MIME type for a file?
You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.
Why can one extension have multiple MIME types?
Different programs and historical usage may assign various MIME identifiers to the same file format. Listing them together helps maintain compatibility across tools.