Scripts are to Microsoft HTML Help what macros are to WinHelp, although scripts can be more powerful. The script contains coded instructions that tell the Help viewer what to do after a user performs an action or even - like clicking a button.
Two common scripting languages that are supported by HTML Help include VBScript and JavaScript. The scripting used in HTML Help is the same kind of scripting that is used by Web pages. Scripts are uncompiled and you can view them in the TrueCode Editor. Since they are not compiled, they do not require any DLLs - everything needed to make them function is built right into the Help topic.