String.prototype.trim=function(){
　　 return this.replace(/(^\s*)|(\s*$)/g, "");
　　}
　　String.prototype.ltrim=function(){
　　 return this.replace(/(^\s*)/g,"");
　　}
　　String.prototype.rtrim=function(){
　　 return this.replace(/(\s*$)/g,"");
　　}

//一个非常实用的javascript读写Cookie函数

function GetCookieVal(offset)
//获得Cookie解码后的值
{
	var endstr = document.cookie.indexOf (";", offset);
	if (endstr == -1)
	endstr = document.cookie.length;
	return unescape(document.cookie.substring(offset, endstr));
}

function SetCookie(name, value)
//设定Cookie值
{
	var expdate = new Date();
	var argv = SetCookie.arguments;
	var argc = SetCookie.arguments.length;
	var expires = (argc > 2) ? argv[2] : null;
	var path = (argc > 3) ? argv[3] : null;
	var domain = (argc > 4) ? argv[4] : null;
	var secure = (argc > 5) ? argv[5] : false;
	if(expires!=null) expdate.setTime(expdate.getTime() + ( expires * 1000 ));
	document.cookie = name + "=" + escape (value) +((expires == null) ? "" : ("; expires="+ expdate.toGMTString()))
	+((path == null) ? "" : ("; path=" + path)) +((domain == null) ? "" : ("; domain=" + domain))
	+((secure == true) ? "; secure" : "");
}

function DelCookie(name)
//删除Cookie
{
	var exp = new Date();
	exp.setTime (exp.getTime() - 1);
	var cval = GetCookie (name);
	document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString();
}

function GetCookie(name)
//获得Cookie的原始值
{
	var arg = name + "=";
	var alen = arg.length;
	var clen = document.cookie.length;
	var i = 0;
	while (i < clen)
	{
		var j = i + alen;
		if (document.cookie.substring(i, j) == arg)
		return GetCookieVal (j);
		i = document.cookie.indexOf(" ", i) + 1;
		if (i == 0) break;
	}
	return null;
}

//end cookie