function isEmailValid(form,elem){
  var emailOK  = true;
  var Temp     = form.elements[elem];
  var AtSym    = Temp.value.indexOf('@');
  var LAtSym   = Temp.value.lastIndexOf('@');
  var AtError1 = Temp.value.indexOf('.@');
  var AtError2 = Temp.value.indexOf('@.');
  var Period   = Temp.value.lastIndexOf('.');
  var Space    = Temp.value.indexOf(' ');
  var Length   = Temp.value.length - 1;
  
  if((AtSym != LAtSym) ||
     (AtSym == Length) ||
     (AtSym < 1) ||
     (AtError1 != -1) ||
     (AtError2 != -1) ||
     (Period == Length ) ||
     (Period == 0) ||
     (Period < AtSym) ||
     (Space  != -1))
  {
   emailOK = false;   
  }
  return(emailOK);
}