javascript - 如何将类添加到给定的元素？(How do I add a class to a given element?)

Question

I have an element that already has a class:

(我有一个已经有一个类的元素：)

<div class="someclass">
    <img ... id="image1" name="image1" />
</div>

Now I want to create a JavaScript function that will add a class to the div (not replace, but add).

(现在，我想创建一个JavaScript函数，该函数将向div添加一个类（不是替换，而是添加）。)

How can I do that?

(我怎样才能做到这一点？)

  ask by Blankman translate from so