Javascript replacing

Hello, i want to replace 'download' to 'download_prev'
ex:

<a href=''><img src='/download-0-756a8f457f516a948b89/00990Nature.jpg'/></a><br/>

i want to make:

<a href=''><img src='/download_prev-0-756a8f457f516a948b89/00990Nature.jpg'/></a><br/>

please only simple js if you can bcoz i will use for opera mini users and no php

Code:

---

var images = document.getElementsByTagName('img');
var pattern = /^\/download/;
var replacement = '/download_prev';
for (var i = 0, len = images.length; i < len; i++) {
        images[i].src = images[i].getAttribute('src').replace(pattern, replacement);
}

---

I hope it's simple enough.