How to make content work with and without javascript
This isn't specific to Drupal but its a javascript technique known as 'unobtrusive javascript'. Not knowing how you are displaying the dialog contents, let's assume this simple case:

&lt;a href="http://link-to-dialog-content" class="dialog-trigger"&gt;See Dialog Content&lt;/a&gt;


and then somewhere else in your code (next to?) you've got a div with your dialog content set to not display, ex:

&lt;div style="display:none"&gt;Your dialog content here .. &lt;/div&gt;


What you want to do is use jquery (you can do this with native javascript but you're using drupal so its already loaded) to bind a click handler to this link. The idea is then that if javascript is not loaded, then the browser will automatically send them on their way. So that would look something like this:

$(".dialog-trigger").click(function() {
   // do your display stuff here, 
   return false;
}


The 'return false' statement at the end is key here to making it so that the link won't be followed.