ng-switch 指令

<!--标准用法-->
<div ng-switch on="showSecret">
    <div ng-switch-when="true">Secrect</div>
    <div ng-switch-default>Won‘t show you my Secrects!</div>
</div>
<!--灵巧用法-->
<li ng-repeat="crumb in crumbs.getAll()">
    <span class="divider">/</span>
    <ng-switch on="$last">
        <span ng-switch-when="true">{{crumb.name}}</span>
        <span ng-switch-default>
            <a href="{{crumb.path}}">{{crumb.name}}</a>
        </span>
    </ng-switch>
</li>
<!--ng-switch-when和-default必须作为属性，不能作为元素标签用-->
<!--例如下面这种写法是不行的！（已验证）-->
<ng-switch on="$last">
    <ng-switch-when="true">{{crumb.name}}</ng-switch-when>
        <ng-switch-default>
            <a href="{{crumb.path}}">{{crumb.name}}</a>
        </ng-switch-default>
</ng-switch>