Js two ways to determine whether a character is a Chinese character

2020-03-30 01:13:45
OfStack

Sometimes it is necessary to determine whether a character is a Chinese character or not, for example, when the user enters a content containing Chinese and English, it is necessary to determine whether it exceeds the specified length. There are usually two ways to do this with Javascript.

1. Use regular expressions


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
　　<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
　　<title>js Determine whether a character is a Chinese character </title>
　　<style type="text/css">
      .content{
          width:350px;
          overflow:hidden;
          border:1px solid #ddd;
      }
　　</style>
<script language="javascript" type="text/javascript"> 
  function CheckChinese(obj,val){     
　　var reg = new RegExp("[\u4E00-\u9FFF]+","g");
　　if(reg.test(val)){     
       alert(" Unable to input Chinese characters! ");  
       var strObj = document.getElementById(obj);  
       strObj.value = "";  
       strObj.focus();          
　　}       
  }
</script>
</head>
<body>
　　<div class="content">
      <div> Test characters: <input id="test" type="text" onblur="CheckChinese('test',this.value)" /> </div>
　　</div>  
</body>
</html>

2. Use Unicode character range

The following method is used to calculate the length of the input string. Otherwise the string length will be 1.


　　function chkstrlen(str)
　　{
　　　　var strlen = 0;
　　　　for(var i = 0;i < str.length; i++)
　　　　{
　　　　　　if(str.charCodeAt(i) > 255) //If it's a Chinese character, add 2 to the length of the string
　　　　　　　　strlen += 2;
　　　　　　else  
　　　　　　　　strlen++;
　　　　}
　　　　return   strlen;
　　}