I have a button (outside of a form) that redirects to another page using the `onclick` attribute that calls `window.location` to redirect the user to another page. This time I can't change the HTML. I am using Safari 4 for testing. How can I click a button that uses the `onclick` attribute and `window.location` to redirect using Safari 4 and Selenium RC PHPUnit Extension?

Here's my HTML:

```
<input type="button" onclick="window.location='/registrations/new'" value="Start a new registration" id="create">

```

**Update:** Alternatively, I'm thinking about doing something where I assert that a location is specified in the `window.location=''`, store that location, and call the `open()` command using that location. Not sure if this is an acceptable approach to testing this.