Element.observe(window, 'load', function() {
	
	var callTimeHiddenElement 	= $('callMeTimeHidden');
	var callTimeElement 		= $('callMeTime');
	var callBackSelect 			= $('callMeBack');
	
	if (callTimeElement && callBackSelect)
	{
		callTimeElement.disable();
		callTimeHiddenElement.enable(); 
		
		Element.observe(callBackSelect, 'change', function(e) 
		{
			if (callBackSelect.options[callBackSelect.selectedIndex].value == 'specified')
			{
				callTimeElement.enable();
				callTimeHiddenElement.disable(); 
			}
			else 
			{
				callTimeElement.disable(); 
				callTimeHiddenElement.enable(); 
			}
		});
	}	
});