Just noticed a quick flaw which works with IE but not Firefox.   I had a table where I was specifying the width.   This was working fine in IE, but strangely Firefox was ignoring the width and scaling the table to match the width of the contents?

Turns  out I was specifying the width as an integer without appending “px”.    So width=100 tells IE to use 100 pixel width but Firefox ignores it.    Change it to “width=100px” and both are happy…

Just had a problem with a website which worked fine in IE, however when viewed in Firefox, some of the <A HREF> links weren’t working!

Turns out it was a problem with the z-axis.   One of the other elements on the page was appearing on top of the links and obscuring them.  By using  “z-index” I was able to re-order the elements, bringing the links to the surface again – and all worked fine again.

Here’s a good description of how to use z-index:

https://developer.mozilla.org/en/Understanding_CSS_z-index/Adding_z-index

Found this website recently – good source for tutorials on developing wordpress themes in CSS:

http://www.wpdesigner.com/