function checkLogin(userName,n) {
	if (n == 0 && userName.value == "键入搜索内容"){userName.value="";userName.style.cssText = "color:#000"}
	if (n == 1){
		if(userName.value == "键入搜索内容"){userName.value="";}
		userName.style.cssText = "color:#000";
	}
	if (n == 2 && userName.value == ""){userName.value = "键入搜索内容";userName.style.cssText = "color:#aaa"}
}