// http://www.w3schools.com/JS/js_cookies.asp
//function that stores the name of the visitor in a cookie variable:
function setCookie(c_name,value,expiredays)
{
	var exdate=new Date();
	exdate.setDate(exdate.getDate()+expiredays);
	document.cookie=c_name+ "=" +escape(value)+
	((expiredays==null) ? "" : ";expires="+exdate.toUTCString());
}

// function that checks if the cookie has been set:
function getCookie(c_name) {
	if (document.cookie.length>0) {
		c_start=document.cookie.indexOf(c_name + "=");
	  	if (c_start!=-1) {
		    c_start=c_start + c_name.length+1;
		    c_end=document.cookie.indexOf(";",c_start);
		    if (c_end==-1) c_end=document.cookie.length;
		    return unescape(document.cookie.substring(c_start,c_end));
	    }
	}
	return "";
}

//function to check if cookie exist and set it if not
function checkCookie()
{
	ScreenRes = getCookie('ScreenRes');
	if (ScreenRes!=null && ScreenRes!="") { 
		//alert('Welcome again '+ScreenRes+'!');  
	}else{
  		ScreenRes  = pageWidth() / pageHeight();
  		if (ScreenRes!=null && ScreenRes!="")   {
    		setCookie('ScreenRes',ScreenRes,365);
    	}
  	}
}