How to HTML-encode a String in JavaScript

As a web developer, you often come across a situation where you need to encode a string into HTML entities.

This is done to avoid cross-site scripting attacks, where malicious code is executed on a web page.

In this Javascript tutorial, we will discuss how to HTML-encode a string in JavaScript.

What is HTML-encoding?

HTML-encoding refers to converting special characters into their equivalent HTML entities.

For example, converting < into < and > into >.

This helps to prevent malicious code from being executed on a web page.

Why do we need to HTML-encode a string?

There are several reasons why you might want to HTML-encode a string:

1. To prevent cross-site scripting (XSS) attacks: XSS attacks are a type of security vulnerability where malicious code is injected into a web page. HTML-encoding helps to prevent these attacks by converting special characters into their equivalent HTML entities.
2. To display special characters: Some special characters may not display properly on a web page, even with proper encoding. HTML-encoding ensures that special characters are displayed correctly.

How to HTML-encode a string in JavaScript

There are several ways to HTML-encode a string in JavaScript. Here, we will discuss two methods:

1. Using the built-in encodeURIComponent() method: This method is used to encode a string for use in a URL. It converts all special characters into their equivalent HTML entities.

var string = "<div>Hello World!</div>";
var encodedString = encodeURIComponent(string);
console.log(encodedString);
// Output: %3Cdiv%3EHello%20World!%3C%2Fdiv%3E

2. Using a third-party library: There are several third-party libraries available for encoding strings in JavaScript, such as the he library.

var he = require("he");
var string = "<div>Hello World!</div>";
var encodedString = he.encode(string);
console.log(encodedString);
// Output: <div>Hello World!</div>

Conclusion

In this tutorial, we have discussed how to HTML-encode a string in JavaScript.

By using either the built-in encodeURIComponent() method or a third-party library, you can ensure that special characters are displayed correctly and prevent cross-site scripting attacks.

Whether you are a beginner or an experienced web developer, HTML-encoding is an essential technique to master.