Document.prerendering is a read-only boolean that is true while the document is prerendering via the Speculation Rules API (MDN).
Read the notes below before you get or set this property. Prefer feature detection when support is limited.
Use document.prerendering. Start with this line.
document.prerendering| Call | What it does |
|---|---|
document.prerendering | Primary signature. |
Built into the browser. Read or assign document.prerendering — no import required.
document.prerendering| Parameter | Description |
|---|---|
| Getter | Required. true while prerendering |
| Setter | Optional. Read-only |
| Return Value | Description |
|---|---|
| * | The current value of document.prerendering. |
document.prerenderingMDN-style status check while a page may be prerendering.
if (document.prerendering) {
console.log("got this far during prerendering!");
} else {
console.log("not prerendering");
}true only during active prerender.MDN pattern: wait for prerenderingchange when prerendering is active.
function initAnalytics() {
console.log("analytics start");
}
if (document.prerendering) {
document.addEventListener("prerenderingchange", initAnalytics, {
once: true,
});
} else {
initAnalytics();
}prerenderingchange runs when the user activates the page.MDN’s combined check for current, past, or no prerender.
if (document.prerendering) {
document.addEventListener(
"prerenderingchange",
() => {
console.log("Prerender activated after this script ran");
},
{ once: true }
);
} else if (
performance.getEntriesByType("navigation")[0]?.activationStart > 0
) {
console.log("Prerender activated before this script ran");
} else {
console.log("This page load was not via prerendering");
}prerenderingchange.activationStart > 0 means activation already happened.Document.prerendering is Experimental with Limited availability on MDN (not Baseline). Feature-detect and keep a normal-load code path.
Read-only boolean for Speculation Rules prerender — support is growing.
Bottom line: Safe to teach with detection. Pair with prerenderingchange and activationStart when measuring or delaying work.
Learn the document’s loading state string.
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