String.prototype.trim=function(){
	return this.replace(/(^\s*)|(\s$)/g,"")	
}
// 通过id获取元素
function $(element){
	return typeof(element)=="string"?(element==""?null:document.getElementById(element)):element
};
// 获取表单项目的值
function $F(element){
	element=$(element);	
	if(!element)return "";
	var s=isNaN(element.length),v="";
	var xElement=s?element:element[0];
	switch(xElement.tagName.toUpperCase()){
		case "TEXTAREA":return xElement.value;
		case "SELECT":
		case "OPTION":
			var os=element.options;
			if(element.multiple){
				for(var i=0;i<os.length;i++)
					if(os[i].selected)v+=","+os[i].value;
				return v.substr(1)
			}else{
				return os[element.selectedIndex].value
			};
		default:
			switch(xElement.type.toUpperCase()){
				case "RADIO":
					if(s){
						return element.checked?element.value:""	
					}else{
						for(var i=0;i<element.length;i++)
							if(element[i].checked)return element[i].value;
						return ""
					};
				case "CHECKBOX":
					if(s){
						return element.checked?element.value:""
					}else{
						for(var i=0;i<element.length;i++)
							if(element[i].checked)v+=","+element[i].value;
						return v.substr(1)
					};
				default:return xElement.value
			}
	}
};
// 异步传输请求
function $Ajax(url,data,respond,cache){
	var object=(function(){
		try{return new XMLHttpRequest()}catch(Exception){};
		try{return new ActiveXObject("Microsoft.XMLHttp")}catch(Exception){};
		try{new ActiveXObject("MSXML2.XMLHttp")}catch(Exception){}
		return null
	})();
	if(object==null)return;
	if(!cache)url+=(url.match("=")?"&":"?")+Math.random();
	if(data==null){
		object.open("Get",url,true)
	}else{
		object.open("Post",url,true);
		object.setRequestHeader("Content-type","application/x-www-form-urlencoded")
	};
	object.onreadystatechange=function(){
		if(object.readyState==4){
			if(object.status==200){
				respond(object)
			}else{
				alert("请求的页面发生错误或不存在！")
			}
		}
	}
	object.send(data)
};
// 异步POST提交表单
function $Submit(form,respond){
	form=typeof(form)=="string"?document.forms[form]:form;
	if(!form)return;
	var eles=form.elements,data="",att,name,project={};
	for(var i=0;i<eles.length;i++){
		att=eles[i].getAttributeNode("name");
		if(att==null)continue;
		name=att.value;
		if(!name||name=="")continue;
		if(!project[name]){
			project[name]=1;
			data+="&"+name+"="+encodeURIComponent($F(form.elements[name]))
		}
	}
	$Ajax(form.getAttributeNode("action").value,data.substr(1),respond)
};
// 获取元素绝对位置
function $Position(element){
	element=$(element);
	var top=element.offsetTop,left=offsetLeft;
	while(element.offsetParent){
		element=element.offsetParent;
		top+=element.offsetTop;
		left+=element.offsetLeft
	}
	return {top:top,left:left}
};
// 获取DOM对象
function $DOM(){
	var db=document.body,de=document.documentElement;
	return {
		width:Math.max(db.scrollWidth,de.scrollWidth),
		height:Math.max(
			Math.max(db.scrollHeight,de.scrollHeight),
			Math.max(db.clientHeight,de.clientHeight)
		),
		top:Math.max(db.scrollTop,de.scrollTop),
		left:Math.max(db.scrollLeft,de.scrollLeft)
	}
}
// 为元素添加事件
function $AddEvent(element,action,method){
	element=$(element);
	if(document.attachEvent){
		element.attachEvent("on"+action,method)
	}else if(document.addEventListener){
		element.addEventListener(action,method,false)
	}
};
function show_products(e){
	var width=960,height=600;
	var left=(window.screen.width-width)/2;
	var top=(window.screen.height-height)/2;
	window.open(e.href,"_blank","scrollbars=1,width="+width+",height="+height+",left="+left+",top="+top);
	return false;
}