Displaying a Java Script dialog box with two buttons. How to handle button press events.

  I am developing and Asp.net website. Occsionally I will have to display
  A Java Script dialog box. The dialog box will have two buttons on it.
  One labeled "Proceed" and the other labeled "Cancel".
  Then I need two Java Script methods to respond to which button was pressed.
  So I suppose my java script methods to handle the button press might look like
  the code below.
  Anyway, I don't know how to invoke these methods when the dialog button are pressed.
  Can someone help me out?
 
<script type="text/javascript">
function SubmitPressed()
{
   /* Perform some logic */  
}
function CancelPressed()
{
   
  /* Perform some logic */
}
</script>
...