title: How to get number in [(ngModel)] in Angular 2?
body: <p>How to get number in [(ngModel)] in Angular 2?</p>
  
  <pre><code>&lt;select [(ngModel)]="levelNum"&gt;
      &lt;option *ngFor="#level of levels" [value]="level.num"&gt;{{level.name}}&lt;/option&gt;
  &lt;/select&gt;
  
  levelNum:number;
  levels:Array&lt;Object&gt; = [
      {num: 0, name: "AA"},
      {num: 1, name: "BB"}
  ];
  </code></pre>
  
  <p>I tried to add <code>type="number"</code> in different places.</p>
  
  <pre><code> &lt;select type="number" [(ngModel)]="levelNum"&gt;
      &lt;option *ngFor="#level of levels" [value]="level.num"&gt;{{level.name}}&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>and </p>
  
  <pre><code> &lt;select [(ngModel)]="levelNum"&gt;
      &lt;option type="number" *ngFor="#level of levels" [value]="level.num"&gt;{{level.name}}&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>But when I select a new item, <code>levelNum</code> still becomes a string.</p>