jQuery.now()?jQuery.now() (alias $.now()) returns the current time as milliseconds since the Unix epoch (since jQuery 1.4.3). Official docs: it is an alias for Date.now().
$.now() → Number (ms since 1970-01-01 UTC)
Date.now() → same idea (prefer this)
// Example shape (value changes every call):
$.now() → 1728000000123| Need | Use |
|---|---|
| Current epoch ms (modern) | Date.now() |
| Timestamp from a Date object | date.getTime() |
| Legacy jQuery only | $.now() (1.4.3–3.x) |
jQuery.now()Call it with no arguments; store or subtract the Number you get.
$.now() (or prefer Date.now()).end - start (both from now).Date.now() instead of $.now().| Piece | Required? | Role |
|---|---|---|
| Arguments | None | Method takes no parameters |
| Return | — | Number — epoch milliseconds |
| Since | — | jQuery 1.4.3 |
now():
return milliseconds since Unix epoch
// Official meaning:
jQuery.now ≡ Date.now
// Elapsed pattern:
start = now()
do work
elapsed = now() - startKeep these facts handy when reading legacy jQuery timing code.
| Topic | Detail |
|---|---|
| Access | jQuery.now() / $.now() |
| Returns | Epoch ms (Number) |
| Alias | Date.now() |
| Deprecated | jQuery 3.3+ |
| Removed | jQuery 4.0 |
| Modern replace | Date.now() |
Run $.now(), compare with Date.now(), or build a cache-bust URL.
Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.
Read the epoch milliseconds and confirm the type.
var timestamp = $.now();
console.log(typeof timestamp); // "number"
console.log(timestamp); // e.g. 1728000000123$.now() needs no arguments.number.$.now vs Date.nowOfficial idea: $.now() is an alias for Date.now().
console.log($.now === Date.now); // true in modern jQuery
var a = $.now();
var b = Date.now();
console.log(typeof a === "number");
console.log(Math.abs(a - b) <= 1); // same clock, within 1 ms$.now to Date.now.Date.now() only.Subtract start from end to get duration in milliseconds.
var start = $.now();
for (var i = 0; i < 500000; i++) { /* work */ }
var elapsed = $.now() - start;
console.log("Elapsed: " + elapsed + " ms");end - start is elapsed milliseconds.Append a changing timestamp so browsers treat the URL as fresh.
var url = "/js/widget.js?v=" + $.now();
console.log(url);
// e.g. /js/widget.js?v=1728000000123$.now() as v.Date.now().Build a one-off element id with a timestamp suffix.
var tempId = "panel-" + $.now();
$("<div></div>")
.attr("id", tempId)
.text("Hello from " + tempId)
.appendTo("#log");$.now() makes a unique string.Check these before relying on $.now() in production.
Calling $.now() on jQuery 4+ throws. Migrate to Date.now() before upgrading.
Epoch time follows the OS clock. NTP adjustments can make elapsed diffs look odd. For short UI timing, performance.now() is steadier.
Two calls in the same millisecond can match. Fine for demos; use a counter or crypto.randomUUID() when uniqueness matters.
$.now() / Date.now() are whole milliseconds. Micro-benchmarks need performance.now().
jQuery.now() needs jQuery 1.4.3–3.x loaded. It is removed in jQuery 4.0. Prefer Date.now() in every modern browser.
Works in Chrome, Firefox, Safari, and Edge when jQuery 1.4.3–3.x is loaded. New projects should call Date.now() instead.
Bottom line: Replace $.now() with Date.now() — same Number, no jQuery dependency.
| Approach | Cost | Best for |
|---|---|---|
Date.now() | O(1), native | All new code |
$.now() | O(1), alias | Legacy jQuery 1.4.3–3.x |
new Date().getTime() | Allocates Date | When you already need a Date |
performance.now() | High-res, relative | Precise duration in the page |
Prefer Date.now() for clarity and future-proofing. The cost difference vs $.now() is negligible; the API status is what matters.
$.now() returns epoch milliseconds.Date.now().Date.now() (gone in jQuery 4).end - start both from now.One line: $.now() is a deprecated alias for Date.now() — use the native method in new code.
Parse JSON strings — and learn why JSON.parse is preferred today.
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