Timeouts and Aborts

Timeouts and Aborts: free step-by-step lesson with examples, common mistakes, and interview tips — part of jQuery Tutorial on Toolliyo Academy.

8 min read Updated 8/23/2026

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jQuery Tutorial · Lesson 48 of 100

Timeouts and Aborts

Setup & DOM ✓ → Events Effects AJAX → Perf & Integrate → Ship & Projects

Events Effects AJAX · 2 — Interact · ~6 min · AJAX and APIs

What is this?

Set timeout in $.ajax so hung calls fail fast. Keep the jqXHR and call .abort() when the user navigates away or starts a newer request.

Why should you care?

Stale QueryVerse responses overwriting newer filters is a classic race — abort the previous call.

See it live — copy this example

Examples include the jQuery 3.7 CDN. Paste into an HTML file or use Run Example to preview.

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>QueryVerse</title>
  <style>
    body { font-family: system-ui, sans-serif; margin: 1.25rem; }
    .box { padding: .75rem; border: 1px solid #ccc; border-radius: 8px; margin: .5rem 0; }
    .muted { color: #666; }
    button { margin-right: .35rem; margin-top: .35rem; }
    input, select, textarea { margin: .25rem 0; }
    table { border-collapse: collapse; width: 100%; }
    th, td { border: 1px solid #ddd; padding: .4rem .55rem; text-align: left; }
    .hidden { display: none; }
    .row-odd { background: #f7f7f7; }
    .active { font-weight: 700; }
    .toast { background: #111; color: #fff; padding: .5rem .75rem; border-radius: 6px; }
  </style>
</head>
<body>
  <input id="q" placeholder="Type to search users">
  <pre id="out" class="box muted"></pre>
<script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
<script>
$(function () {
  var current = null;
  $('#q').on('input', function () {
    var q = $(this).val().trim();
    if (current) current.abort();
    if (!q) { $('#out').text(''); return; }
    $('#out').text('Searching…');
    current = $.ajax({
      url: 'https://jsonplaceholder.typicode.com/users',
      dataType: 'json',
      timeout: 5000
    }).done(function (users) {
      var hits = users.filter(function (u) {
        return u.name.toLowerCase().indexOf(q.toLowerCase()) !== -1;
      }).map(function (u) { return u.name; });
      $('#out').text(hits.join('\n') || 'No hits');
    }).fail(function (xhr, status) {
      if (status === 'abort') return;
      $('#out').text('fail: ' + status);
    });
  });
});
</script>
</body>
</html>

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>QueryVerse</title>
  <style>
    body { font-family: system-ui, sans-serif; margin: 1.25rem; }
    .box { padding: .75rem; border: 1px solid #ccc; border-radius: 8px; margin: .5rem 0; }
    .muted { color: #666; }
    button { margin-right: .35rem; margin-top: .35rem; }
    input, select, textarea { margin: .25rem 0; }
    table { border-collapse: collapse; width: 100%; }
    th, td { border: 1px solid #ddd; padding: .4rem .55rem; text-align: left; }
    .hidden { display: none; }
    .row-odd { background: #f7f7f7; }
    .active { font-weight: 700; }
    .toast { background: #111; color: #fff; padding: .5rem .75rem; border-radius: 6px; }
  </style>
</head>
<body>
  <input id="q" placeholder="Type to search users">
  <pre id="out" class="box muted"></pre>
<script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
<script>
$(function () {
  var current = null;
  $('#q').on('input', function () {
    var q = $(this).val().trim();
    if (current) current.abort();
    if (!q) { $('#out').text(''); return; }
    $('#out').text('Searching…');
    current = $.ajax({
      url: 'https://jsonplaceholder.typicode.com/users',
      dataType: 'json',
      timeout: 5000
    }).done(function (users) {
      var hits = users.filter(function (u) {
        return u.name.toLowerCase().indexOf(q.toLowerCase()) !== -1;
      }).map(function (u) { return u.name; });
      $('#out').text(hits.join('\n') || 'No hits');
    }).fail(function (xhr, status) {
      if (status === 'abort') return;
      $('#out').text('fail: ' + status);
    });
  });
});
</script>
</body>
</html>

Result