How to make a jQuery "$.post" request synchronous

javascript

async-programming

callbacks

promises

byAnton Shumikhin·Feb 19, 2025

To execute a synchronous POST in jQuery, substitute your $.post with an $.ajax call and set async: false:

$.ajax({
  type: 'POST',
  url: '/path/to/server',
  data: { param: 'value' },
  async: false,
  success: function(data) {
    // Data received, unleash your inner data monster! 🦖
  }
});

Heads-up: Synchronous AJAX has been deprecated. It's known to practice the "freeze and squeeze" on your user interface. It's generally better to dance with asynchronous calls using callbacks, promises, or async/await.

Workaround: Handling User Interaction

When syncing up AJAX with user interaction, let's consider an alternative approach. Here's how you can juggle:

For operations like form submissions, you can emulate synchronous flow using asynchronous AJAX coupled with promises.
You can keep the user at bay while AJAX is in action using the BlockUI plugin or a manual method such as display overlays.
Don't forget to remove the BlockUI or overlay in AJAX's .done() callback, freeing user interaction once more.

Eureka! This method maintains a responsive UI while maintaining a better hold over your state of affairs.

Deprecation Rally: "async: false"

async: false with jQuery may remind you of the good ol' days, but proceed with caution due to deprecation issues and the chance of a frozen UI. Let's get with the times:

Replace synchronous AJAX calls with asynchronous ones. Time to dust off your old friends callbacks, promises, or if you're feeling fresh, async/await.
Consider using jQuery Promises. They'll handle the complex AJAX flows and keep your UI as fluid as a sea otter's slide.
Always test your new implementations; unlike lasagna, they're not always better the second time.

The Alternatives: Beyond Synchronous $.ajax()

If synchronous requests give you the heebie-jeebies, the following alternatives might just be your asier-safer:

HTML5 Web Workers: Let them toil in the background.
Server-side sessions or databases: These guys can look after the state for you; it's what they do best!
localStorage or indexedDB: For state management on the client side - when the client is king.

Bear in mind: all of these alternatives are ready to roll without freezing the UX with synchronous calls.

Becoming the Synchronous Sensei

Sometimes, the world just wants you to go against the current and make use of synchronous behavior:

Use these calls wisely and where it's expected - like file downloads.
Always nudge the user when a process is running. A little spinner or progress bar can go a long way.
Set a reasonable timeout; your user interface doesn't want to be locked in forever!

Stick to these best practices to mitigate some of the downsides of synchronous AJAX.

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