How do I determine firefox and mac?

Question

I'm working on a display bug in another developer's code. I've got it working everywhere except firefox on a mac. When a user is on firefox and a mac, the page display is off slightly.
I can remedy this problem with a little hack of my style sheet. How can I identify when a user is using firefox on a mac?
Is there anything along these lines
<!--[if IE]>
<style type="text/css">
that can identify the browser AND operating system on a mac?

Answer 1

Unfortunately your page is off in not only Firefox mac but Safari also and I suspect every other browser too.
You CANNOT put an absolutely positioned layer in a <td> cell the way you are doing it.
The reason I suspect the page is out of line and you are struggling to match everything up is because the absolutely positioned layer will stay exactly where it is whilst the other elements center themselves in the browsers window according to how wide the browers view port is.
You need to lock that absolutely positioned layer in position relative to the <td> cell it is in. Then it will move with the rest of the page.
You can do that by wrapping it in a relatively positioned <div> (as below)
<div id="wrapper" style="position: relative;">
  <div class="mainContentWork">
</table>
</div><!-- mainContentWork -->
</div><!-- end wrapper -->
</td>
Then tweak the css until you have it in the correct position.
.mainContentWork {   
    position: absolute;
    left: 23px;
    top: 1px;
    background-image: url(../images/mainBkgrd_work.jpg);
    background-repeat: no-repeat;
    height: 707px;
    Width: 757px;
Using absolutely positioned layers I'm afraid youre doomed to a slow and frustrating death