jQuery jQuery.now() Method

What You’ll Learn

The jQuery.now() utility returns the current time as a millisecond timestamp — the same value as native Date.now(). This tutorial covers syntax, timing patterns, comparisons with other date APIs, practical cache-busting and ID generation, and migration notes for jQuery 3.3+.

Introduction

Timestamps appear everywhere in web development: measuring how long an animation takes, busting browser caches on script URLs, stamping log entries, or generating temporary IDs. jQuery added jQuery.now() (also written $.now()) in version 1.4.3 as a shorthand for getting the current time without leaving the jQuery namespace.

Under the hood, $.now() is an alias for Date.now() — the native JavaScript method that returns milliseconds since January 1, 1970 UTC. jQuery deprecated the helper in version 3.3 and removed it in 4.0. Modern code should call Date.now() directly.

Understanding the jQuery.now() Method

jQuery.now() takes no arguments and returns a Number — the number of milliseconds that have elapsed since the Unix epoch. Each call produces a fresh value reflecting the moment the function runs.

The result is not a formatted date string and not a Date object. It is a plain number like 1721289600123, ideal for arithmetic: subtract a start timestamp from an end timestamp to get elapsed milliseconds.

📝 Syntax

General form of jQuery.now:

jQuery.now()
// or
$.now()

Parameters

• None — this method does not accept any arguments.

Return value

• A Number representing the current time in milliseconds since the Unix epoch (January 1, 1970 UTC).

Official jQuery API description

var timestamp = $.now();
// Same value as Date.now()
// e.g. 1721289600123

Examples Gallery

Each example uses $.now(). Open DevTools or use the Try-it links. Example 1 shows the basic timestamp the jQuery API describes.

var timestamp = $.now();

console.log(typeof timestamp); // "number"
console.log(timestamp > 0);    // true — always positive since 1970

number
true

var jqueryTime = $.now();
var nativeTime = Date.now();

console.log(jqueryTime === nativeTime); // true (same millisecond)

true

var start = $.now();

// Simulate work
for (var i = 0; i < 100000; i++) { /* loop */ }

var elapsed = $.now() - start;
console.log("Took " + elapsed + " ms");

Took 0 ms
(or a small positive number depending on device)

var scriptUrl = "/js/widget.js?v=" + $.now();

console.log(scriptUrl);
// "/js/widget.js?v=1721289600123"

/js/widget.js?v=1721289600123
(actual number varies per call)

var tempId = "panel-" + $.now();

console.log(tempId);
// "panel-1721289600123"

$("<div>").attr("id", tempId).appendTo("body");

panel-1721289600123
(actual number varies per call)

🚀 Common Use Cases

• Elapsed timing — measure AJAX round-trips or animation duration.
• Cache busting — append ?v=timestamp to script or CSS URLs.
• Unique IDs — stamp dynamically created DOM nodes or plugin instances.
• Debounce / throttle — compare last-run timestamps on scroll or resize handlers.
• Logging — record when events fired in legacy debugging code.
• Rate limiting — reject requests that arrive too soon after the previous one.

📝 Notes

• Available since jQuery 1.4.3; deprecated in jQuery 3.3; removed in jQuery 4.0.
• Alias for Date.now() — not for new Date() or formatted date strings.
• Returns epoch milliseconds, not seconds — divide by 1000 only when you need Unix seconds.
• For high-resolution relative timing, use performance.now() (different origin and precision).
• System clock changes (NTP adjustments) can affect elapsed-time math over long intervals.
• Replace $.now() with Date.now() when upgrading to jQuery 4.

💡 Best Practices