Thesupports() static method of theHTMLScriptElement interface provides a simple and consistent method to feature-detect what types of scripts are supported by the user agent.

The method is expected to returntrue for classic and module scripts, which are supported by most modern browsers.

Syntax

HTMLScriptElement.supports(type)

Parameters

type

A string literal that indicates the type of script for which support is to be checked.Supported values are case sensitive, and include:

"classic"

Test ifclassic scripts are supported."Classic" scripts are the normal/traditional JavaScript files that predate module scripts.

"module"

Test ifmodule scripts are supported.

"importmap"

Test ifimport maps are supported.

"speculationrules"

Test ifspeculation rules are supported and enabled.

Any other value will cause the method to returnfalse.

Return value

Returnstrue if the indicated script type is supported andfalse otherwise.

Examples

The code below shows how to check ifHTMLScriptElement.supports() is defined, and if so, to use it to test whether particular types of scripts are supported.

const log = document.getElementById("log");function checkSupport(type) {  const result = HTMLScriptElement.supports(type) ? "true" : "false";  log.textContent += `HTMLScriptElement.supports('${type}') is ${result}\n`;}if (typeof HTMLScriptElement.supports === "undefined") {  log.textContent = "HTMLScriptElement.supports() method is not supported";} else {  // Check if various script types are supported  checkSupport("module");  checkSupport("classic");  checkSupport("importmap");  checkSupport("speculationrules");  // Any other value will cause the method to return false  checkSupport("anything else");}

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Specifications

Browser compatibility

See also

• HTMLScriptElement
• <script>
• JavaScript modules
• Worker constructor