CHM is a Microsoft html help format. Actually, a CHM file is a compressed html archive. Although more and more eBooks are using PDF as their format, but there are still many CHM eBooks.
When you are reading a CHM eBook, maybe you want to annotate it like annotating a PDF document, but Microsoft only provided a simple viewer to read the this kind of file, it cannot be used to annotate your eBooks. How to annotate your CHM eBooks? Maybe there are some CHM author tools can do that, but they are too expensive for most people and these tools actually are for the eBook authors.
There are also some cheap ways to do that. For example, You can Download the Microsoft HTML Help Workshop from Microsoft official site, which is a Microsoft Official CHM author tool, you can not only use it to create your own chm documents, also it provides a function for converting a CHM file to standard HTML files. You can edit these files with html tools. In this way, you need to reorganize the contents yourself, because these decompiled files do not contain the necessary files for compiling to the original CHM file. The decompiling can only extract the html files from this chm file, not including the project file, content file and index file and so on.
Actually, the 7-zip can also decompile the chm files. Using the 7-zip, you can not only get the html files, but also chm project file, index file and content file. Then after editing these files you want, you can use Help Workshop to compile these files into a chm file. When you open the output eBook file, you will see the changes you did.
If you like PDF format and had purchased a PDF annotation tool, you can convert it into a PDF Document. Many tools, free or charge can help you to do that. Then you need some tools for editing your PDF document. Adobe Acrobat provides powerful functions for annotating PDF documents, but it is expensive. You can also try some 3rd party tools, which also provide edit functions for editing PDF files. But some people do not like the converted page layout from a CHM file.
The above ways for annotating your chm eBooks maybe too tedious, is there a way to annotate CHM eBooks directly? Yes, with Beyond CHM, you don’t need to convert the CHM eBook to any other files for annotation. You can annotate CHM eBooks directly using Beyond CHM.
Beyond CHM is a powerful chm reader and editor, running in the MS Windows environment. It allows user to open multiple tabs at the same time. By using it, users can edit the chm documents, including highlighting the text, changing the text foreground color, removing the contents, adding new elements and so on, all the changes can be saved persistently. Additionally, user can switch Beyond CHM between reader mode and editor mode easily. In the reader mode, users can zoom in and zoom out chm pages freely. Beyond CHM is a good Microsoft HTML Help Executable replacement.
If you want to annotate CHM eBooks, you’ll find it is really a useful tool.