ChmZoomer

ChmZoomer gives you handy full page zoom functionality in all other browser-based applications, such as Chm files, e-Books, and RSS Reader. That is just like in IE7 or 8. The shortcut keys are the same as IE and Firefox. It can be torturous and straining to read ant-like text in high resolution screen. The plug-in lets you zoom-in and zoom-out the font size in CHM freely. So the CHM would be comfortable to read. Press [CTRL +] or [CTRL Mouse wheel up] to zoom in, press [CTRL -] or [CTRL Mouse wheel down] to zoom out, and reset zoom to 100 percent with Ctrl-0.

Limitations:

Some features disabled