var IE4 = (document.all && !document.getElementById) ? true : false;
    var NS4 = (document.layers) ? true : false;
    var IE5 = (document.all && document.getElementById) ? true : false;
    var IE6 = (document.all && document.getElementById) ? true : false;
    var NS6 = (document.getElementById && !document.all) ? true : false;
    var IE  = IE4 || IE5 || IE6;
    var NS  = NS4 || NS6;
    var Mac = (navigator.platform.indexOf("Mac") == -1) ? false : true;

	var agt=navigator.userAgent.toLowerCase();
	var is_ie = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
	var is_major = parseInt(navigator.appVersion);
	var is_ie5 = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );

    var sheet;

    if( NS )
    {
        sheet = "tagleen_ns.css";
    }
    else if( Mac )
    {
        sheet = "tagleen_mac.css";
    }
    else if( IE5 )
    {
        // Let's assume all the rest of the browsers are sane
        // and standard's compliant.
		if( window.opera )
		{
				sheet = "tagleen_opera.css";
		}
		else
		{
			sheet = "tagleen_ie.css";
		}
    }
    else
    {
		sheet = "tagleen.css";
    }

	//alert(sheet);
	//alert(window.opera);

   document.write("<link rel=\"stylesheet\" href=\"css/"+sheet+"\">");

	if (NS4)
	{
		alert("Please, upgrade your browser to version 7.2");
	}
	if (is_ie5){
		alert("Please, upgrade your browser at least to version 5.5");
	}