function isNumberKey(evt)
{
   var charCode = (evt.which) ? evt.which : event.keyCode
   if (charCode > 31 && (charCode < 48 || charCode > 57))
      return false;
   return true;
}


// =============== Default functions ========================
// ==========================================================

function top() {
  window.scrollTo(0, 0);
}


function back() {
  history.back();
 }




 function addLoadEvent(func) {
 	var oldonload = window.onload;
 	if (typeof window.onload != 'function') {
 		window.onload = func;
 	} else {
 		window.onload = function () {
 			if (oldonload) {
 				oldonload();
 			}
 			func();
 		}
 	}
 }