<scripttype="text/javascript"src="js/jquery-1.9.1.js"></script>
<script>
	$(function(){
		$.ajax({
			url:'http://www.xxx.com/users/syncLogin',type:"GET",dataType:"jsonp",jsonp:'callback',success:function(data){
				document.cookie="ECS_ID="+data.id;
				alert(data.id);
			}
		});
	});
</script>

publicfunctionsyncLogin(){
	$this->autoRender=false;
	$callback=$_GET['callback'];
	echo$callback.'('.json_encode(array('id'=>$_COOKIE[ECS_ID])).')';
}

第二版：第一版cookie改变后需要刷新才生效

$.ajax({
	url:'http://www.xxx.com/users/syncLogin',success:function(data){
		varcookie_str=document.cookie;
		vardate=newDate();
		date.setTime(date.getTime()+365*24*3600*1000);
		document.cookie="ECS_ID="+data.id+";expires="+date.toGMTString();
		cookie_str=cookie_str.replace(/;/g,';');
		varcookie_array=cookie_str.split(';');
		for(vari=0,len=cookie_array.length;i<len;i++){
			if(cookie_array[i].split('=')[0]=='ECS_ID'){
				if(cookie_array[i].split('=')[1]!=data.id+''){
					location.reload(1);
				}
			}
		}
	}
});

第三版：提取function

functionsetCookie(c_name,value,expiredays)
{
	varexdate=newDate();
	exdate.setDate(exdate.getDate()+expiredays);
	document.cookie=c_name+"="+escape(value)+
	((expiredays==null)?"":";expires="+exdate.toGMTString());
}
functiongetCookie(c_name)
{
	varcookie=document.cookie;
	varcookie_len=document.cookie.length;
	if(cookie_len>0){
	c_start=cookie.indexOf(c_name+"=")
		if(c_start!=-1){
			c_start=c_start+c_name.length+1;
			c_end=cookie.indexOf(";",c_start);
		if(c_end==-1){
			c_end=cookie_len;
		}
			returnunescape(cookie.substring(c_start,c_end));
		}
	}
	return"";
}
$.ajax({
	url:'http://www.xxx.com/users/syncLogin',success:function(data){
		varcookie_str=document.cookie;
		varcookie_ecs_id=getCookie('ECS_ID');
		setCookie('ECS_ID',data.id,365);
		if(cookie_ecs_id!=data.id+''){
			location.reload(1);
		}
	}
});