navigator.javaEnabled() historically asked whether the browser’s Java plugin (applets) was available. MDN: today it always returns false. Baseline Widely available — not Deprecated, Experimental, or Non-standard.
Pass the required arguments shown below. Check return values and browser support before you rely on the result.
Syntax
Call navigator.javaEnabled. Start with this line.
JavaScript
navigator.javaEnabled()
Call
What it does
navigator.javaEnabled()
Primary signature.
navigator.javaEnabled(...)
Call with the arguments your case needs.
Built into the browser. Call javaEnabled(...) on a Navigator — no import required.
Library declarations
JavaScript
navigator.javaEnabled()
Parameters
This member has no parameters beyond those shown in the signature.
Return Value
Return Value
Description
*
Always false
JavaScript Examples
Example 1 — Call Returns false (MDN)
MDN’s contract is simple: the boolean is always false.
No arguments. Call with an empty argument list (MDN).
Boolean false. Every modern engine follows this contract.
Widely present. Baseline since July 2015 (MDN).
Literacy value. Know the return — do not trust it for features.
Example 2 — Why if (javaEnabled()) Is Dead
MDN’s own example: the condition is always false, so the body never runs.
JavaScript
if (window.navigator.javaEnabled()) {
console.log("Java plugin available"); // never prints
} else {
console.log("Java plugin unavailable");
}
// Prefer real feature detection for modern APIs.
MDN: this method always returns false. It historically reported whether the browser’s Java plugin was available for applets.
No. MDN marks it Baseline Widely available (since July 2015). It is not Deprecated, Experimental, or Non-standard — so no status banner is required. Its result is simply always false.
Modern browsers no longer support the old Java browser plugin / applets model. The method remains for compatibility but cannot report a working Java plugin.
Not for real feature decisions. Calling it is harmless, but if (navigator.javaEnabled()) blocks never run. Prefer feature detection for the APIs you actually need.
No. Call navigator.javaEnabled() with no arguments. It returns a boolean (always false).
No. It was about the browser’s old Java plugin for applets — not about whether your backend uses Java, Node, or another language.
