Detecting Users Browser

As a web developer, the issues i always encounter are from web browsers,..

When creating CSS, Javascript codes, specially with Ajax, there will be always a conflict on Web Browsers.. Common problems are floating Divs.. Thats why you need to detect users browsers so that you could switch on your style sheets.. 

In Php heres a very easy code: 

if (strpos($_SERVER['HTTP_USER_AGENT'], ‘Firefox’) !== FALSE) {

//Your code goes in here 

}

List of Common Browsers:

 Firefox = ‘Firefox’

IE = ‘MSIE’

Netscape = ‘Netscape’

Opera= ‘Opera’

 By the time your page was loaded the $_SERVER['HTTP_USER_AGENT'] automatically registers your web browser name.