Angularjs 切换<；a>；使用Angular.js初始化

我正在使用Angular.js创建一个简单的选项卡式界面，但我想在我刚才单击的任何链接上切换一个

活动的类。这是我的密码

    <header>
    <nav>
    <a href ng:click="selected=1">Home</a>
    <a href ng:click="selected=2">About</a>
    <a href ng:click="selected=3">Work</a>
    <a href ng:click="selected=4">Blog</a>
    <a href ng:click="selected=5">Login</a>
    </nav>
    </header>

    <article ng:hide="selected == 2 || selected == 3 || selected == 4 || selected == 5" >
    <section>
    <h2>1</h2>
    </section>
    </article>

    <article ng:show="selected == 2">
    <section>
    <h2>2</h2>
    </section>
    </article>


    <article ng:show="selected == 3">
    <section>
    <h2>3</h2>
    </section>
    </article>


    <article ng:show="selected == 4">
    <section>
    <h2>4</h2>
    </section>
    </article>


    <article ng:show="selected == 5">
    <section>
    <h2>5</h2>
    </section>
    </article>


. 
任何帮助都将不胜感激
 使用
ng class
指令：

<header>
        <nav>
            <a href ng:click="selected=1" ng-class="{active: selected == 1}">Home</a>
            <a href ng:click="selected=2" ng-class="{active: selected == 2}">About</a>
            <a href ng:click="selected=3" ng-class="{active: selected == 3}">Work</a>
            <a href ng:click="selected=4" ng-class="{active: selected == 4}">Blog</a>
            <a href ng:click="selected=5" ng-class="{active: selected == 5}">Login</a>
        </nav>
</header>

使用
ng class
指令：

<header>
        <nav>
            <a href ng:click="selected=1" ng-class="{active: selected == 1}">Home</a>
            <a href ng:click="selected=2" ng-class="{active: selected == 2}">About</a>
            <a href ng:click="selected=3" ng-class="{active: selected == 3}">Work</a>
            <a href ng:click="selected=4" ng-class="{active: selected == 4}">Blog</a>
            <a href ng:click="selected=5" ng-class="{active: selected == 5}">Login</a>
        </nav>
</header>