function onkeypressEvent()
{
//0-9
 if(event.keyCode < 48 || event.keyCode>57)
 {
//逗号，点号，减号，空格
  if (event.keyCode != 44 && event.keyCode != 45 && event.keyCode != 46 && event.keyCode != 32)
  {
//退格键
   event.keyCode = 8;
  }

   }
}