You would be surprised to know that the biggest Internet Explorer issue I am facing while writing rather complex cross-browser javascript code is related to just a comma.

In javascript array if you add a comma after the last element in the array then Internet Explorer fails with a variety of undecipherable (Microsoft style) error messages. Firefox works fine. And that is the biggest and only problem I am facing with Internet Explorer while writing cross-browser javascript code. And do you know who takes the credit for that? - Ex tJS.

Ext JS is a high quality cross platform Javascript library with very impressive features out of the box by Jack Slockum. I am using it primary for displaying large amount of data and manipulating them using the Grid component. Ext JS can speed up your Web 2.0 application development by miles. Ext JS on frontend and Java on backend is what programming nirvana is made of.

Update: I did face a second bug with IE.