Simple question. I am trying to change all the image alt tags on my site using jQuery. The issue I'm having is that all my images have existing alt tags that I want to add to. Currently my code won't do anything, here is what I have placed just before closing the 

```
<script>
$("img").attr({
alt: "This is some alt text"
});
</script>

```

Can someone help me figure out what is wrong here. Thanks.