How to escape html with jQuery

jQuery is a very popular JavaScript library that is widely used in the field of web development. When we need to display some HTML code on the page, in order to prevent injection attacks, the HTML code must be escaped. So, how can jQuery escape HTML code? This article will introduce it in detail.

1. Why HTML escaping is needed

In web applications, the data input by users often contains HTML codes. If these data are output directly to the page, it may cause injection attacks. . HTML injection attack refers to an attacker inserting HTML code into user input or other variables of a web application through clever means, so that it is interpreted and executed in the browser, and achieves the purpose of the attack, such as stealing User's sensitive information or tampered application data, etc. To prevent this attack, we need to escape the input data containing HTML code.

2. Methods of HTML escaping

When escaping HTML, we can use the two methods provided by jQuery: text() and html(). The core difference between the two methods is that the text() method will escape the tags in the HTML code, while the html() method will not escape the tags. Next, we will explain these two methods in detail.

1. Use text() method for HTML escaping

The text() method can escape the special characters contained in HTML code into their entity form. Special characters include:

& (ampersand)
" (double quote)
' (single quote)
 (greater-than)

For example, we need to escape the following HTML code:

<div>hello,world</div>

We can use the following code to escape:

var html = "<div>hello,world</div>";
var safeHtml = $("
").text(html).html();
console.log(safeHtml); // "hello,world"
 in the above In the example, we first use the text() method to escape the HTML code, assign the HTML code containing special characters to a div element, and then use the html() method to take out the innerHTML attribute of the div element, that is, the pairing is completed. Escape processing of HTML code. Finally, we get a string without labels. 
Use the html() method for HTML escaping
The html() method will not escape the tags in the HTML code, it will only escape the tags in the code. Escape special characters. Therefore, if we need to output code containing HTML tags, we must use the html() method instead of the text() method. 
For example, we need to output the following HTML code: 
<div>hello,world</div>
Use the html() method to process as follows: 
var html = "<div>hello,world</div>";
var safeHtml = $("
").html(html).html();
console.log(safeHtml); // "<div>hello,world</div>"
In the above example, we use html( ) method to output the HTML code, first assign the code to a div element, and then take out the innerHTML attribute of the div element to get the string containing the label. 
3. How to choose to use text() or html() method
For the string that needs to be output, if it contains HTML tags, you must use the html() method; if it does not contain HTML tag, you can use the text() method for output. During development, in order to avoid HTML injection attacks as much as possible, it is recommended to use the text() method for HTML escaping. At the same time, for the sake of code readability, it is recommended to encapsulate the escape operation into a function and use it when needed. 
In short, for strings that need to be HTML escaped, you can easily escape them by using jQuery's text() or html() method, avoiding unnecessary security issues. 

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