HTML <input> autofocus 属性

设置 "First name" 输入字段在页面加载时自动获得焦点：

<form action="demo_form.html">
  First name: <input type="text" name="fname" autofocus><br>
  Last name: <input type="text" name="lname"><br>
  <input type="submit">
</form>

http://www.runoob.com/tags/att-input-autofocus.html