background von div per Javascript ändern

[Tim]

hallo

---

function test(box_1)
         {
         document.getElementByID(box_1)div.style.background="green";
         }
...

<div id="box_1">Mein Inhalt</div>

...

<a href="javascript:test()">Farbe wechsel Dich</a>

probiere mal
document.getElementByID('box_1').style.background="green";

und
<a href="javascript:void()" onclick="test">Farbe wechsel Dich</a>