Simple HTML/Javascipt Div with Password

<script type="text/javascript">
  function isValid(){
  var keyvalue = document.getElementById('keyvalue').value;
  if (keyvalue == "hcas")
    {document.getElementById('divPassword').style.display = "block";}
  else
    {alert('ACCESS DENIED')}
  }
</script>

<form name="PasswordField" action="">
  Type Password Below:</br>
  <input type="text" id="keyvalue" name="keyvalue" onkeydown = "if (event.keyCode == 13) document.getElementById('subPass).click()">
  <input type="button" id="subPass" value="ACCESS" onclick="isValid(this);">
</form>

<div id="divPassword" style="display:none;">
  </br>
  <p>ACCESS GRANTED</p></br>
  This is password div
</div>