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URLSearchParams: append() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨April 2018⁩.

Note: This feature is available in Web Workers.

The append() method of the URLSearchParams interface appends a specified key/value pair as a new search parameter.

As shown in the example below, if the same key is appended multiple times it will appear in the parameter string multiple times for each value.

Syntax

append(name, value)

Parameters

name: The name of the parameter to append.
value: The value of the parameter to append.

Return value

None (undefined).

Examples

Adding the same parameter multiple times

const url = new URL("https://example.com?foo=1&bar=2");
const params = new URLSearchParams(url.search);

// Add a second foo parameter.
params.append("foo", 4);
// Query string is now: 'foo=1&bar=2&foo=4'

Specifications

Specification
URL> # dom-urlsearchparams-append>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`append`	49	17	29	36	10.1	49	29	36	10.3	5.0	49	10.3