How to solve the problem of garbled characters in javascript

In web development, garbled characters are a very common problem. When we display non-ASCII characters (such as Chinese, Japanese, Korean, etc.) on a web page, garbled characters often appear. This is mainly due to problems converting between different encodings.

In JavaScript, you will also encounter garbled characters. When using AJAX to request data, parse data and other operations, if non-ASCII characters are involved, you will need to face the problem of garbled characters. So, how to solve the garbled problem in JavaScript?

1. Understand character encoding

Before discussing how to solve the problem of garbled characters, we need to understand some basic knowledge of character encoding.

1. ASCII code

ASCII code is a 7-bit character encoding, containing 128 characters. These include 26 uppercase letters, 26 lowercase letters, 10 numbers and 33 special characters.

2. Unicode code

Unicode code is an encoding that can represent all characters in the world. It includes more than 1.1 million different characters.

3. UTF-8 encoding

UTF-8 encoding is a variable-length encoding method that can represent any character in the Unicode code. It uses 1 to 4 bytes to represent each character, and the specific byte length is determined by the Unicode code value.

2. Methods to solve the garbled code problem

There are many ways to solve the garbled code problem. Here are some commonly used methods.

1. Set the html file encoding method

In the html file, you can specify the character encoding method of the document by setting the charset attribute of the tag. For example, if we want to set the encoding method of the document to UTF-8, we can add the following code in the tag:

<meta charset="UTF-8">

In this way, when the browser parses the document, it will be in accordance with UTF-8 8 method to decode the content in the document to avoid garbled characters.

2. Convert the string to the correct encoding method

In JavaScript, we can use the four functions encodeURI, encodeURIComponent, decodeURI and decodeURIComponent to perform encoding and decoding operations . Among them, the encodeURI and encodeURIComponent functions can convert specific characters into URI encoding format, and decodeURI and decodeURIComponent can decode strings in URI encoding format into original strings. These functions ensure that strings are converted in the correct encoding to avoid garbled characters.

3. Set the Content-Type header of the AJAX request

When using AJAX to request data, we can specify the requested data type and encoding method by setting the Content-Type header. . For example, if we want to send data in UTF-8 encoding, we can set the following Content-Type header when sending the request:

xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');

In this way, when the server receives the request, it will encode it in UTF-8 Parse the request data to avoid garbled characters.

4. Download files using Blob objects

In JavaScript, we can use Blob objects to generate binary data and save it as a file for downloading. When generating a Blob object, you can specify the encoding method of the data to ensure that the data in the file is saved in the correct encoding method to avoid garbled characters. For example, if we want to generate a Blob object in UTF-8 encoding, we can use the following code:

const blob = new Blob([data], { type: 'text/csv; charset=UTF-8' });

5. Parsing XML data using the text attribute

In JavaScript, use When the XMLHttpRequest object requests XML data, you can set the responseType attribute to "text" to ensure that the XML data is parsed according to the correct encoding method to avoid garbled characters. For example, we can set the responseType attribute of the XMLHttpRequest object using the following code: When parsing data, you can also set the responseType attribute to "text" to ensure that the JSON data is parsed according to the correct encoding method to avoid garbled characters. For example, we can use the following code to set the responseType attribute of the XMLHttpRequest object:

const xhr = new XMLHttpRequest();
xhr.responseType = 'text';
xhr.open('GET', url);
xhr.send();

3. Summary
6. The problem of garbled characters is a common problem in Web development, and it is also a relatively cumbersome problem. In JavaScript, we can set the encoding method of html files, convert strings to the correct encoding method, set the Content-Type header of AJAX requests, use Blob objects to download files, and use text attributes to parse XML and JSON data, etc. method to solve the problem of garbled characters. At the same time, we also need to understand some common character encoding knowledge to better understand the nature of the garbled problem.

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