I have found that the
JavaScript & DHTML Cookbook
by Danny Goodman
has saved me countless hours in creating cross-browser compatible javascript. It's a very well-written book. In particular, he shows ways to "normalize" your document model in code so that your business logic will be cross-browser compatible.

>Has anyone ever had a problem running JavaScript using a Mozilla Firefox browser?
>
>Here's why I am asking this question...
>
>I have some e-commerce web pages in which I use JavaScript where the user chooses from a drop-down list and the name they choose gets plugged into an e-mail message in the form of an purchase order. But when the user uses a Firefox browser the selected name is missing from the purchase order.
>
>This bad behavior does not happen when I use AOL or IE browers.
>
>Any ideas?