JavaScript only displays Chinese

JavaScript is a commonly used programming language and is widely used in various application scenarios such as website development, game development, and mobile applications. However, sometimes we need to limit JavaScript to only display Chinese, which helps to improve the readability of the website. sex and user experience. This article will introduce how to implement a method of displaying only Chinese in JavaScript.

1. Use Chinese character sets

JavaScript supports the Unicode standard. Unicode includes character sets for various languages, including Chinese character sets. Therefore, we can limit JavaScript to only display Chinese by defining the use of Chinese character sets in the program. For example:

<meta charset="UTF-8"> 

Adding the above code to HTML means using UTF-8 encoding and supporting the Chinese character set. In this way, the content output by JavaScript will automatically be encoded and converted, and only Chinese will be displayed.

2. Limit the character set range

In addition to using the Chinese character set, you can also display only Chinese by limiting the character set range. For example, we can define a function to determine whether a string contains only Chinese characters. If the string does not meet the conditions, an empty string will be returned.

function onlyChinese(str) {
  var len = str.length;
  var result = '';
  for (var i = 0; i < len; i++) {
    var charCode = str.charCodeAt(i);
    if (charCode >= 0x4e00 && charCode <= 0x9fa5) { //UTF-8中文编码范围
      result += str.charAt(i);
    }
  }
  return result;
}

The above code means that only when the character encoding is within the UTF-8 Chinese encoding range, the character will be added to the return result, and other characters will be discarded, thereby achieving the effect of displaying only Chinese characters.

3. Use regular expressions

In JavaScript, regular expressions are a very convenient tool that can be used to match content that matches a specific pattern in a string. Therefore, we can use regular expressions to achieve the effect of displaying only Chinese. For example, the following is a regular expression that only retains Chinese characters:

var chineseReg = /[^u4e00-u9fa5]/g;
str.replace(chineseReg, "");

In the above code, chineseReg means to match all characters that are not within the UTF-8 Chinese encoding range, that is, non-Chinese characters. Use the replace method to delete non-Chinese characters. Chinese characters, and finally returns a string containing only Chinese characters.

To sum up, we can achieve the effect of JavaScript only displaying Chinese by defining the use of Chinese character sets, limiting the character set range and using regular expressions, improving the readability and user experience of the website.

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