Validation without form submission

Validation without form submission

Hi All,
 
I have a form, on which is a button - When the user clicks the button, a function is called which posts the form data to a web service.
 
I have used the validation plugin to, which was very easy - What a fantastic bit of coding that plugin is!
 
The problem I have is that the validation only fires when I use a submit button.
  1. <input type="submit" value="submit"/>
But not when my button is clicked, which runs my function.
 
I understand why this is - The validation plugin wants the form to be submitted.
 
Is there any way I can cause the validation to run and return its result? My function can then either do nothing if the validation fails, or go ahead and post the user entered data to the web service if the validation passes. Obviously I would need to do this without the form actually submitting.
 
Any help greatly appreciated - I've tried a few ideas I found whilst Googling on this, but nothing has worked so far.
 
Thank you.