​x
 
<html>
<head>
<script type="text/javascript">
function alertLength()
  {
  alert(document.getElementById("password1").maxLength)
  }
</script>
</head>
<body>
​
<form>
<input type="password" id="password1" maxLength="8" />
<input type="button" id="button1" onclick="alertLength()" value="Alert maxLength" />
</form>
​
</body>
</html>
​