How to prevent clicking disabled "Place order" button from redirecting to homepage?

Hi all. I use 1.3.5 SP4 with ajax enabled one-page checkout.

My problem is:

How to prevent clicking disabled “Place order” button (when it is not up to step five and the button is gray)from redirecting to homepage? Just make it stay still or unclickable.

The link of the disabled “Place order” button is something like this [url]http://localhost/cscart/#[/url] .

Any ideas to solve this one? Or it will disappear after going live?

Thanks in advance.