Definition and Usage

The decodeURI() function is used to decode a URL that was encoded using encodeURI().

It decodes only the special characters encoded by encodeURI().

Features

  • Does not decode characters that encodeURI() does not encode, such as /, ?, :, &, and #.
  • To decode URLs that include these characters, use decodeURIComponent() instead.

Basic Example

JavaScript 
const uri = "https://www.example.com/?x=Sample Value";
const encoded = encodeURI(uri);

console.log(encoded);
// Output: "https://www.example.com/?x=Sample%20Value"

const decoded = decodeURI(encoded);

console.log(decoded);
// Output: "https://www.example.com/?x=Sample Value"

The decodeURI() function has the following syntax:

Syntax

JavaScript 
decodeURI(encodedURI)

Parameters

Parameters of the decodeURI() function
encodedURI The encoded URI string to decode. This function decodes the given encoded URI string back into its regular text form.

Return value

Returns a new string that is the decoded version of the given encodedURI string.

Characters Not Encoded by decodeURI()

The decodeURI() function decodes only the characters encoded by encodeURI(). However, it does not decode the # character.

Example

JavaScript 
const originalURI = "https://example.com/email list"; // URL with a space
const encodedURI = encodeURI(originalURI);            // Space encoded as %20
const decodedURI = decodeURI(encodedURI);             // Decoding back to original

console.log(encodedURI); // Output: "https://example.com/email%20list"
console.log(decodedURI); // Output: "https://example.com/email list"

This clearly demonstrates how encodeURI() and decodeURI() work with special characters in URLs.

Important Note

Be careful when decoding a URI encoded with encodeURIComponent() using decodeURI(), as it may only partially decode the string.

JavaScript 
const uriComponent = "https://www.example.com/search?q=JavaScript & Web Development";
const encodedUriComponent = encodeURIComponent(uriComponent);

console.log(encodedUriComponent);
// Output: "https%3A%2F%2Fwww.example.com%2Fsearch%3Fq%3DJavaScript%20%26%20Web%20Development"

const decodedUri = decodeURI(encodedUriComponent);

console.log(decodedUri);
// Output: "https%3A%2F%2Fwww.example.com%2Fsearch%3Fq%3DJavaScript %26 Web Development"

As shown above, decoding a URI encoded with encodeURIComponent() using decodeURI() only partially decodes it. In such cases, you should use decodeURIComponent() to fully decode the string.

JavaScript 
const uriComponent = "https://www.example.com/search?q=JavaScript & Web Development";
const encodedUriComponent = encodeURIComponent(uriComponent);
console.log(encodedUriComponent);
// Output: "https%3A%2F%2Fwww.example.com%2Fsearch%3Fq%3DJavaScript%20%26%20Web%20Development"

const decodedUri = decodeURIComponent(encodedUriComponent);
console.log(decodedUri);
// Output: "https://www.example.com/search?q=JavaScript & Web Development"

Specifications

Specification for JavaScript decodeURI() Function
Specification
decodeURI() ECMAScript Language Specification
#sec-decodeuri-encodeduri

Browser compatibility

Browser compatibility for JavaScript decodeURI() Function
Function
Desktop Chrome
Chrome
DesktopDesktop Edge
Edge
Desktop Firefox
Firefox
Safari
Safari
decodeURI() 1 12 1 1.1

See also