设置与获取 cookie
function setCookie(c_name,value,expiredays){
var exdate=new Date();
exdate.setTime(exdate.getTime() + expiredays);
document.cookie=c_name+ "=" +escape(value)+
((expiredays==null) ? "" : ";expires="+exdate.toGMTString());
}
function getCookie(objName){//获取指定名称的cookie的值
var arrStr = document.cookie.split("; ");
for(var i = 0;i < arrStr.length;i ++){
var temp = arrStr[i].split("=");
if(temp[0] == objName)
return unescape(temp[1]);
}
}