<p>I want to create a javascript badge that displays a list of links. We host the javascript on our domain.  Other sites can put an empty div tag on their page and at the bottom a reference to our javascript that would render the content in the div tag.  How do you implement something like this?</p>

just as you say, have them put a div at the bottom of their page:
```
```
<div id="mywidget"></div>
```
```
then have them link to your javascript:
```
```
<script type="text/javascript" src="http://yourdomain.com/mywidget.js"></script>
```
```
then have them alter their body tag, or onload to call your script
```
```
<script type="text/javascript">
  document.body.onload = loadYourWidget();
</script>
```
```