CSS, javascript, ajax and different browsers

["Jim Franz" <franz400@xxxxxxxxxxxx>]

In dealing with customer web pages (order entry) how are others handling browser differences? 
Do you dumb the features down to a level most browser accept or code sections for different browsers? This is search & data entry & not so much point & click, & project on a skinny budget. 

Depending upon whose stats (this is w3schools), 
Internet Exp8 16.2%  IE7   7.8%    IE6  6.7% Total 30.7
Firefox 4.0    0.6%  3.6  35.2%    3.5  6.1% Total 45.8
Chrome 6.0     1.4%  5.0  15.1%    4.0  0.3% Total 17.0
Safari S5      2.6%  ...                            3.5

We want to set a minimum standard for browsers.
All of this will be in rpgle cgi.
Jim Franz