function regInput(reg)
{
  var srcElem = event.srcElement
  var oSel = document.selection.createRange()
  var srcRange = srcElem.createTextRange()
  oSel.setEndPoint("StartToStart", srcRange)
  var num = oSel.text + String.fromCharCode(event.keyCode) + srcRange.text.substr(oSel.text.length)
  event.returnValue = reg.test(num)
}