function get_randomCssNum()
    {
        var ranCssNum= Math.floor(Math.random()*4);
	    //var ranCssNum= Math.floor(Math.random()*Number of CSS you Have);
        return ranCssNum;
    }

        function getaCss()
        {
            var whichCss=get_randomCssNum();

        var cssName=new Array(4)
         // var cssName=new Array(Number of CSS you Have)
         cssName[0]="<link rel='stylesheet' type='text/css' href='/includes/css/web/random/xlife01.css'>";
         cssName[1]="<link rel='stylesheet' type='text/css' href='/includes/css/web/random/xlife02.css'>";
         cssName[2]="<link rel='stylesheet' type='text/css' href='/includes/css/web/random/xlife03.css'>";   
         cssName[3]="<link rel='stylesheet' type='text/css' href='/includes/css/web/random/xlife04.css'>";
  	    return cssName[whichCss];
      }
      document.write(getaCss());