function numbersonly(myfield, e, dec) {
 var key;
 var keychar;

 if (window.event)
   key = window.event.keyCode;
 else if (e)
   key = e.which;
 else
   return true;
 keychar = String.fromCharCode(key);

 // control keys
 if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27) )
   return true;

 // numbers
 else if ((("0123456789").indexOf(keychar) > -1))
   return true;

 // decimal point jump
 else if (dec && (keychar == ".")) {
   myfield.form.elements[dec].focus();
   return false;
 } else
   return false;
}