我想让输入的数字是6位数或9位数.不少于6位，不在6到9位之间，不超过9位数字.我能知道怎么做吗？代码将在下面插入
<label class="control-label col-sm-5" for="badgeid" style="margin-left: -50px;">ID:</label>;
<div class="col-sm-4">;
<p class="form-control-static" style="margin-top: -6px;">
<input type="number" class="form-control" id="secuid" name="secuid" min="0" placeholder="Enter ID" value=" $return_id">
<label class="control-label col-sm-6" style="color: red; font-size: 12px; margin-right: 20px;display: contents;">** 6 Digit ST Employee ID / 9 SecurityID **</label>
</p>
</div>
<div class="col-sm-10"></div>
下面是Javascript.
var secuid = document.translot.secuid.value;
if (secuid == null || secuid == ""){
alert("Please Insert the ID.")
return false;
}