ie6 = 		(navigator.userAgent.indexOf("MSIE 6.")==-1) ? false : true;
ie7 = 		(navigator.userAgent.indexOf("MSIE 7.")==-1) ? false : true;
ie8 = 		(navigator.userAgent.indexOf("MSIE 8.")==-1) ? false : true;
firefox = 	(navigator.userAgent.indexOf("Firefox")==-1) ? false : true;
opera = 	(navigator.userAgent.indexOf("Opera")  ==-1) ? false : true;

var head = document.getElementsByTagName('head')[0];

function loadCSS () {
	link = document.getElementById('cssLink');
	if (ie6) {		
		link.href = 'css/prezentyIE6.css'
	} else if (ie7) {		
		link.href = 'css/prezentyIE7.css'
	} else if (ie8) {
		head.removeChild(link);
	} else if (opera) {		
		link.href = 'prezentyOpera.css'
	} else {		
		head.removeChild(link);
	}
}

window.onload=loadCSS;