链式方法

/*方法一、对象封装
var Base = {
	getId : function (id) {
		return document.getElementById(id)
	},
	getName : function (name) {
		return document.getElementsByName(name)
	},
	getTagName : function (tag) {
		return document.getElementsByTagName(tag);
	}
};
*/

//方法二
var $ = function () {
	return new Base();
}

function Base() {}
	//创建一个数组，来保存获取的节点和节点数组
	Base.prototype.elements = [];
	
	//获取ID节点
	Base.prototype.getId = function (id) {
		this.elements.push(document.getElementById(id));
		return this;
	};
	
	//获取元素节点
	Base.prototype.getTagName = function (tag) {
		var tags = document.getElementsByTagName(tag);
		for (var i = 0; i < tags.length; i ++) {
			this.elements.push(tags[i]);
		}
		return this;
	};


Base.prototype.css = function (attr, value) {
	for (var i = 0; i < this.elements.length; i ++) {
		this.elements[i].style[attr] = value;
	}
	return this;
}

Base.prototype.html = function (str) {
	for (var i = 0; i < this.elements.length; i ++) {
		this.elements[i].innerHTML = str;
	}
	return this;
}

Base.prototype.click = function (fn) {
	for (var i = 0; i < this.elements.length; i ++) {
		this.elements[i].onclick = fn;
	}
	return this;
}