function HandleEnterKey (ButtonName, event) {  
  var DefaultButton; 
  if (document.all){  // for IE brower
    DefaultButton = eval('document.all.' + ButtonName);
    if (event.keyCode == 13) {
      event.returnValue = false;
      event.cancel = true;
      DefaultButton.click();
    } 
  }

else if (document.getElementById){  // for FireFox brower
    DefaultButton = document.getElementById(ButtonName);
    if (event.which == 13){   
        event.returnValue=false;   
        event.cancel = true;   
        DefaultButton.click();   
    }   
    }  
else if(document.layers){   
    DefaultButton = document.layers[ButtonName];
    if(event.which == 13){   
        event.returnValue=false;   
        event.cancel = true;   
        DefaultButton.click();   
    }   
    }

}