Div float:left in Firefox

Hi, I have a proble with a popup window in Firefox. I putted this code:

body{margin:0}

Now there is no blank spaces as borders, this is good , but my first div have:
float:left; width:xx; height: xx

The result is a blank space over this div, and this is only for Firefox, IE shows it fine

Help me If you can, thanks

Spider

 

padding:0?

Can't really tell without seeing your site/code.

 

The Moz default style sheet calls for a list to have 1em margin, top and bottom.

ul, menu, dir {
  display: block;
  list-style-type: disc;
  margin: 1em 0;
  -moz-padding-start: 40px;
}

Code (markup):

You may set it as you please.

cheers,

gary

 

Thanks a lot