//根据名称获取cookie值
getCookie:function(cname){
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++)
{
var c = ca[i].trim();
if (c.indexOf(name)==0){
return c.substring(name.length,c.length);
}
}
return "";
},