Javascript How to call a function when we choose Stay on Page in Chrome

Please check my code in Chrome Browser, if you hit refresh you will be prompted with 2 options.

1. Leave This Page and


2. Stay on This Page

When I click the 2. Stay on this page button it must activate my custom function displayMsg()

Can any one provide me solution?

<script type="text/javascript">
 function displayMsg() {
     alert('my text..');
 }
 </script>
 <script type="text/javascript">
 window.onbeforeunload = function(evt) {
   var message = 'Please Stay on this page and we will show you a secret text.';
   if (typeof evt == 'undefined') {
       evt = window.event;
   }       
   if (evt) {
       evt.returnValue = message;
       return message;
   }
   trace(evt);
 } 
 </script>
 

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