Great way to debug javascript
1. Download MS Script Debugger from Microsoft website and install it. This is the download address:
http://download.microsoft.com/download/winscript56/install/1.0a/NT45XP/EN-US/scd10en.exe
2. Modify IE settings:
In IE's Options-->Advanced, there are two options that are checked by default:
Disable Script Debugging(Internet Explorer)
Disable Script Debugging(Other)
In Chinese, it may be "Disable script debugging", uncheck these two items.
3. Add debugger where debugging is required; for example: <script language=javascript>
..
debugger;
..
</script>
This is a breakpoint. When running here, it will interrupt and enter debugging mode: 