选项卡（面向对象）

摘要：普通写法转换过程先变型尽量不要出现函数嵌套函数可以有全局变量把中不是赋值的语句放到多带带函数中改成面向对象全局变量就是属性函数就是方法中创建对象改指向事件或定时器问题现要求再创建一个选项卡，自动轮播，只需新增修改和新增一个方法

html:

    
    
    
    
111
    
222
    
333
 

css:

#div1 div{width: 200px; height: 200px;border:1px #000 solid; display: none;}
.active{background:#f00;}

js:

// 普通写法

    window.onload = function () {
        var oParent = document.getElementById("div1");
        var aInput = oParent.getElementsByTagName("input");
        var aDiv = oParent.getElementsByTagName("div");
        for (var i = 0; i < aInput.length; i++) {
            aInput[i].index = i;
            aInput[i].onclick = function () {
                for (var i = 0; i < aInput.length; i++) {
                    aInput[i].className = "";
                    aDiv[i].style.display = "none"
                }
                this.className = "active";
                aDiv[this.index].style.display = "block"
            }
        }
    }
    

转换过程
-先变型 尽量不要出现函数嵌套函数,可以有全局变量,把onload中不是赋值的语句放到多带带函数中

    var oParent = null;
    var aInput = null;
    var aDiv = null;
    window.onload = function () {
        oParent = document.getElementById("div1");
        aInput = oParent.getElementsByTagName("input");
        aDiv = oParent.getElementsByTagName("div");
        init();
    }

    function init() {
        for (var i = 0; i < aInput.length; i++) {
            aInput[i].index = i;
            aInput[i].onclick = change;
        } 
    }

    function change() {
        for (var i = 0; i < aInput.length; i++) {
            aInput[i].className = "";
            aDiv[i].style.display = "none"
        }
        this.className = "active";
        aDiv[this.index].style.display = "block"
    }
    

//改成面向对象
全局变量就是属性 函数就是方法 onload中创建对象 改this指向(事件或定时器问题)

    window.onload = function () {
       var t1 = new Tab()
       t1.init();
    }
    function Tab() {
        this.oParent = document.getElementById("div1");
        this.aInput = this.oParent.getElementsByTagName("input");
        this.aDiv = this.oParent.getElementsByTagName("div");
    }
    Tab.prototype.init = function () {
        var This = this;
        for (var i = 0; i < this.aInput.length; i++) {
            this.aInput[i].index = i;
            this.aInput[i].onclick = function (){
                This.change(this);
            }
        } 
    }
    Tab.prototype.change = function (obj) {
        for (var i = 0; i < this.aInput.length; i++) {
            this.aInput[i].className = "";
            this.aDiv[i].style.display = "none"
        }
        obj.className = "active";
        this.aDiv[obj.index].style.display = "block"
    }
    

现要求再创建一个选项卡，自动轮播，只需新增div2 修改init和新增一个autoPlay方法

    window.onload = function () {
       var t1 = new Tab("div1")
       t1.init();
       var t2 = new Tab("div2")
       t2.init();
       t2.autoPlay();
    }
    function Tab(id) {
        this.oParent = document.getElementById(id);
        this.aInput = this.oParent.getElementsByTagName("input");
        this.aDiv = this.oParent.getElementsByTagName("div");
        this.iNow = 0;
    }

    Tab.prototype.autoPlay = function () {
        var This = this;
        setInterval(function () {
            if(This.iNow == This.aInput.length-1) {
                This.iNow = 0;
            }else {
                This.iNow++;
            }
            for (var i = 0; i < This.aInput.length; i++) {
                This.aInput[i].className = "";
                This.aDiv[i].style.display = "none"
            }
            This.aInput[This.iNow].className = "active";
            This.aDiv[This.iNow].style.display = "block"
        }, 2000)
    }