jquery的隐式链初探

看了下jquery的源码，特意分析下其中的隐式链的实现方式。

<div id="box" class="sd dd">box</div>

<div id="box2">box</div>
<p>fwef</p>
<p>fwef</p>
<p>fwef</p>
<p>fwef</p>
<p>fwef</p>
<p class="sd dd">fwef</p>
<script type="text/javascript">



function $(){
		return new YY();
	};

function getClassName(name,context){
		var arr=[],e,patter=new RegExp(name);
		context=context||document;
		e=context.getElementsByTagName("*");
		for(var i=0;i<e.length;i++){
				if(e[i].className.match(patter)){
						arr.push(e[i]);
					};
			};
		return arr;
	};

function YY(){
	//存放节点的数组
	this.elements=[];
	//获取id
	this.getId=function(name){
			this.elements.push(document.getElementById(name));
			return this;
		};
	//获取标签
	this.getTag=function(tagname,context){
			context=context||document;
			var eles=context.getElementsByTagName(tagname);
			for(var i=0;i<eles.length;i++){
				this.elements.push(eles[i]);
				};
			return this;
		};
	//获取class
	this.getClass=function(name,context){
		context=context||document;
		var eles;
		if(document.getElementsByClassName){
			eles=context.getElementsByClassName(name);
		}else{
			eles=getClassName(name,context);	
		};
		for(var i=0;i<eles.length;i++){
			this.elements.push(eles[i]);
			};
		return this;
	};
	
};
YY.prototype={
	css:function(attr,val){
			for(var i=0;i<this.elements.length;i++){
					this.elements[i].style[attr]=val;
				};
			return this;
		},
	size:function(){
		return this.elements.length;
		}
	
	
	};
var y=new YY();

$().getClass("dd",document.body).css("backgroundColor","red");