Introduction

If you need several scripts to load asynchronously and then want code to run only after both the DOM and those scripts are ready, the real problem is coordination. $(document).ready(...) only tells you the DOM is ready; it does not guarantee that independently loaded scripts have finished downloading and executing.

The clean solution is to treat script loading as asynchronous work, wait for all of it to finish, and only then run the dependent callback. In jQuery-era code, $.getScript() plus $.when() is the usual pattern.

Load Scripts with $.getScript

A basic async script load looks like this:

$.getScript('/js/plugin-a.js');

That fetches and executes the script asynchronously, but by itself it does not coordinate multiple loads or tell you when every dependency is ready.

Wait for Multiple Scripts

Use the jQuery deferreds returned by $.getScript() and combine them with $.when():

1$(function () {
2  $.when(
3    $.getScript('/js/plugin-a.js'),
4    $.getScript('/js/plugin-b.js'),
5    $.getScript('/js/plugin-c.js')
6  ).done(function () {
7    initializePage();
8  }).fail(function () {
9    console.error('One or more scripts failed to load');
10  });
11});

This means:

• wait until the DOM is ready
• start all script requests asynchronously
• run initializePage() only after every script has loaded successfully

That is the key structure missing from many ad hoc callback chains.

Why document.ready Alone Is Not Enough

A common mistake is this:

1$.getScript('/js/plugin-a.js');
2$.getScript('/js/plugin-b.js');
3
4$(function () {
5  initializePage();
6});

This only guarantees DOM readiness, not script readiness. The scripts might still be loading when initializePage() runs, which can create intermittent errors such as missing functions or undefined plugins.

Keep Dependency Order in Mind

If the scripts depend on each other, asynchronous loading still needs ordering. For example, if plugin-b.js requires plugin-a.js, load them sequentially instead of in parallel:

1$(function () {
2  $.getScript('/js/plugin-a.js')
3    .done(function () {
4      $.getScript('/js/plugin-b.js')
5        .done(function () {
6          initializePage();
7        });
8    })
9    .fail(function () {
10      console.error('Script loading failed');
11    });
12});

Parallel loading is best only when the scripts are truly independent.

Modern Note

In modern code, native promises, dynamic import(), bundlers, or module systems are usually cleaner than orchestrating many jQuery script loads. But if you are maintaining a jQuery-based codebase, $.getScript() plus deferred coordination is still a sound approach.

Think in Terms of Readiness Conditions

The page is really ready only when both prerequisites are true: the DOM is ready and the required scripts are loaded. Framing it that way helps avoid the common mistake of treating those two conditions as if they were the same event.

Once you frame it that way, the control flow becomes much easier to design and debug.

It also makes later maintenance less fragile when another dependency is added.

That can be the difference between a one-off workaround and a dependable loading strategy.

It also keeps startup code easier to reason about under failure conditions.

Common Pitfalls

• Assuming $(document).ready() means async scripts are already loaded.
• Loading dependent scripts in parallel when they actually require sequence.
• Running initialization code outside the combined success callback.
• Ignoring script-load failures and then debugging strange runtime errors later.
• Treating jQuery script loading as if it were a full dependency management system.

Summary

• 'document.ready only guarantees DOM readiness, not external script readiness.'
• Use $.getScript() to load scripts asynchronously.
• Use $.when() when several independent scripts must all finish before initialization.
• Load scripts sequentially if one depends on another.
• Keep the post-load callback inside the success path that actually waits for the scripts.