Debugging JavaScript

CS346

IE Javascript Debugging Aids

• From IE6 on default: no debugging aid for Javascript• Change setting:

– Tools > Internet Options > Advanced tab– uncheck the box “Disable script debugging”– check the box “Display a notification about every script error”– press “Apply” button

• See 6A-8debug.html• http://www.microsoft.com/scripting/debugger/default.htm

IE6

Error Message in previous IE versions

IE6

New IE Error Message

IE6

IE8

Firefox

• Download and install JavaScript Debugger– Venkman - code name for Mozilla's JavaScript

Debugger.• https://addons.mozilla.org/en-US/firefox/addon/216/

Open Tool>Error Console:you will get many warnings. Look for the red errors

Error Console of Firefox

Netscape Javascript Debugger

• Tools > Web Development > JavaScript Console• Keep the JavaScript Console open when using Netscape to

display a document with Javascript• After debugging, use the clear button on the console.

Otherwise the old error message remains and may cause confusion

• Reference:• http://www.mozilla.org/projects/venkman/