Jak wypełnić formy zmiennymi z MIB'a

mib_js_fill.htm

<form name="userinfo" method="get" action="info.html">
  <p>Please give us your information, so that we can send
  you spam.</p>
  <p>Name: <input type="text" name="name"/></p>
  <p>E-Mail: <input type="text" name="email"/></p>
  <p>Sex: <select name="sex">
            <option>Male</option>
            <option>Female</option>
            <option>Other</option>
          </select></p>
  <p><input name="send" type="submit" value="Send!"/></p>
</form>

<script language="JavaScript">
  var usrFrm = document.forms.userinfo;
  val a = usrFrm.elements.name;
  a = "Nowa wartosc";
</script>