How to find button control in form template using javascript?

Princy, 

I haver implemented the above code and it works really well in my project and allows me to achieve my goal.  

However, when I add a RadAjaxManger to the page I can no longer find my button using JavaScript to retrieve the value and I receive the error in the console "Uncaught TypeError: Cannot read property 'value' of null"

 Any help would be appreciated.

Regards 

Chris