cfmessagebox

I am trying to use cfmessage box to confirm prior to deleting a record.  I have a delete button that I am diplaying the fessage box using onclick.  The problem I am having is the cfmessagebox pop's up, but the record gets deleted anyway and the cfmessagebox goes away.  Basically, the form is getting submitted regardless.  I am thinking I am doing something wrong here, but can someone point me in the right direction.  Below is come code snippets:

cfmessagebox code:

<cfmessagebox type="confirm" name="confirmdelete" title="Delete Employee?"

     message="Are you sure you want to delete this employee?"

     buttonType="YesNo" icon="warning" labelYes="Yes" labelNo="No">

Button code:            

<button type="submit" id="delete_button" name="delete_button" onClick="javascript:ColdFusion.MessageBox.show('confirmdelete');">Delete</button>

I am pretty sure I should change the button type to "button" rather than submit.  Then, use calbackhandler to submit the form.  However, once the form is submitted, I check for which button is pressed using:

<cfif isDefined("form.delete_button")>

I need to submit the form using javascript, then make sure, after the form is submitted, to make sure the above if statement is true.

Any ideas on what I am doing wrong?  Or, any better ways to do this?