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]);
	}
}

function addCookie(objName,objValue,objHours){//添加cookie
	var str = objName + "=" + escape(objValue);
	if(objHours > 0){//为0时不设定过期时间，浏览器关闭时cookie自动消失
		var date = new Date();
		var ms = objHours*3600*1000;
		date.setTime(date.getTime() + ms);
		str += "; expires=" + date.toGMTString();
	}
	document.cookie = str;
}

function delCookie(objName){
	var exp = new Date();
	exp.setTime(exp.getTime() - 1);
	document.cookie=objName +"=;expires="+exp.toGMTString();
}