Customizing Alert Boxes

Hi Experts,

Currently we have an option, were in a message will pop up every 20 minutes in an application.

and we used java scripting for this.

But, now our customer wants to change the symbol in the alert message.

This is the sample code of how i am currently wrking out the same using javascripts.

< s c r i p t  l a n g u a g e = " J a v a s c r i p t " >
  v a r   w a i t  =  1200;
  v a r   l v _ c n t  =  1;
  v a r   s t o p ;
  f u n c t i o n  s t a r t C l o c k ( )
    {
     w a i t  = w a i t  - l v _ c n t ;
     s t o p  = s e t T i m e o u t ( " s t a r t C l o c k ( ) " ,   1 0 0 0 );
     i f ( w a i t = = 0 )
     {
a l e r t ( "   H e l l o   W o r l d  " ) ;
     w a i t = 1 2 0 0 ;
      }
    }
    s t a r t C l o c k ( ) ;
< / s c r i p t >

Is der a way i can change the symbol of the alert box or do i have to go to VBscripting. If tats the only option then pls let me know which part i need to change for VBscripting..