<form method=post action="">
<input type="text" id="bzscs" maxlength="11">
</form>
<script language="JavaScript">
<!--
alert(document.getElementById("bzscs").getAttribute("maxlength"))
//-->
</script>
<input type="text" id="bzscs" maxlength="11">
</form>
<script language="JavaScript">
<!--
alert(document.getElementById("bzscs").getAttribute("maxlength"))
//-->
</script>
注意大小写 maxLength