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;
}