help me please to fix that difference between the Firefox and the IE

hello,
iam updating my header with search box upon it ,so i made the input text height 30 px and the button pic height gonna be 31 px ,but i got the problem on that addition 1px .

on the Firefox, the 1 px is down . but on the IE the 1 px in up

i tried so hard to fix that but i didn't succeed , so i attached 2 pics for the Firefox and the IE , beside here is my code , and please help me to fix that , thanks

 

Maybe it's position : absolute;

 

Have you tried to reinstall the firefox Mozilla? That Might help to reset those scripts.