Vad gör denna kod?

Vad gör denna kod?

<script language="javascript" type="text/javascript">
<!-- hide begin
  function ValidateInput(frm) {
    var msg = "";
    if (!frm.CallerName.value) {
      msg += ' - enter your login name\n';
    } else {
      var chkRegExp = /[^A-Za-z0-9&_]/;
      var isValid = !chkRegExp.test(frm.CallerName.value);
      if (!isValid) {
        msg += ' - provide valid LOGIN NAME, e.g. lastnameab\n';
      }
    }
    if (!frm.CallerDept.value) msg += ' - enter your department\n';
    if (frm.CallerDept.value == 'dummy') msg += ' - select your department\n';
    if (!frm.CallerExt.value) {
      msg += ' - enter your extension\n';
    } else {
      var chkRegExp = /[^x0-9 -]/;
      var isValid = !chkRegExp.test(frm.CallerExt.value);
      if (!isValid) {
        msg += ' - provide valid extension, e.g. 7676 or x7430\n';
      }
    }
    if (!frm.ProblemDesc.value) msg += ' - enter request description\n';
    // E-mail address
    var em = frm.CallerEMail.value;
    // ... empty is allowed - no notifications
    if (em != "") {
      // ... has to end with @domain.com
      if (em.indexOf('@domain.com') == -1) {
        msg += ' - enter your e-mail address\n';
      }
    }

    if (msg.length > 0) {
      alert('Please correct the following:\n\n' + msg);
      return false;
    } else {
      return true;
    }
  }

/*
  function EMailFix(frm) {
    var sEMail=frm.CallerEMail.value;
    if ((sEMail.indexOf('@') == -1) && (sEMail != ""))
    {
      frm.CallerEMail.value = frm.CallerEMail.value + "@domain.com";
    }
  }
*/

  function SetFocus() {
    document.main_form.CallerEMail.focus();
  }
// hide end -->
</script>

...och hur skriver jag ut värdet på det som står innan @domain.com?