js 输入框验证问题

一开始input中可输入内容的要求都写到后台，实际上可以在前端js中加正则验证

//var LengNum=Request.Form["otherjudge"].Tostring().Length;

//var LengNum = OtherJudge.Length;
//if (LengNum > 7)
//{
// req.msg = "最多可输入7个汉字！";
// req.code = 1;
//}

js:

<input autocomplete="off" class="layui-input" onkeyup="value = value.replace(/[^u4E00-u9FA5]/g, '')" onbeforepaste="    clipboardData.setData('text', clipboardData.getData('text').replace(/[^u4E00-u9FA5]/g, ''))" maxlength=7 name="otherjudge" id="otherjudge">