Haven\'t touch javascript for 3 years. Just got a javascript project and wanted to know any new ways or tools emerged these years to debug javascript? I used alert 3 years
For IE (which I don't suggest using), the latest version (IE8) includes developer tools.

For Firefox, there's an extension called Firebug that has DOM manipulation, a JS console, and more.

WebKit (used in Safari and Chrome) has a built-in Web Inspector that includes a JS debugger, along with a DOM outline and manipulation tools, and a JS console.
