function chkEmpty(field, msg)
{
  if(field.value.search(/\S/) != -1) return true;
  alert(msg);
  field.focus();
  return false;
}

function chkEmail(field)
{
  if(field.value.search(/^([A-Za-z0-9_\.+-]+@([A-Za-z0-9-]+\.)+[A-Za-z0-9-]+)?$/) != -1) return true;
  alert("Email address is invalid.");
  field.focus();
  return false;
}

function chkNumber(field)
{
  if(field.value.search(/^\d*$/) != -1) return true;
  alert("Please enetr a number");
  field.focus();
  return false;
}