Ok this is seemingly impossible to get right. I have a text box and a select box. I want them to be the same width exactly so they line up on the left margin and the right m
Different browsers apply different styles by default. I found that resetting both margin and padding to 0 makes both elements equal widths in both Firefox and Chrome.
Test
I personally like to use a minimal CSS reset stylesheet like YUI CSS Reset before attempting to make a design look great in multiple browsers.