It's not JavaScript itself!

It's Microsoft's own extension and its coined term "Dynamic HTML".
FireFox is more "standard" compliant. Standards are those recommended by W3C. IE is less complaint. For example, the right column shouldn't be moved at all on this page http://www.w3.org/Style/CSS/ -- a bad CSS implementation in IE.

Most IE only stuff (other than ActiveX controls) on Microsoft website can be done nicely using web standards (CSS, DOM, JavaScript/ECMAScript).

Even former Microsoft program manager prefers Firefox (www.joelonsoftware.com 6/15/2004) -- Great Minds Think Alike. Ahah :-)