js检测是否存在中文

代码如下：

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>checkbox</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
</head>
<body>

</form>
<script type="text/javascript">

function funcChina(){
var obj = document.getElementsByTagName('input')[0].value;
var patthrn=/.*[\u4e00-\u9fa5]+.*$/;
if(patthrn.test(obj))
{
alert("不能含有汉字！");
return false;
}

}