Network Tab for AJAX
Network Tab for AJAX: free step-by-step lesson with examples, common mistakes, and interview tips — part of jQuery Tutorial on Toolliyo Academy.
On this page
jQuery Tutorial · Lesson 82 of 100
Network Tab for AJAX
Setup & DOM ✓ → Events Effects AJAX ✓ → Perf & Integrate ✓ → Ship & Projects
Ship & Projects · 4 — Build · ~10 min · Debug and Modernize
What is this?
DevTools Network shows method, URL, status, headers, and response for each $.ajax call. Filter by Fetch/XHR to isolate QueryVerse traffic.
Why should you care?
You cannot fix fail handlers you have not observed — Network is the ground truth.
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>
<button type="button" id="go">Fire XHR</button>
<p id="out" class="muted">Open Network → Fetch/XHR, then click</p>
<script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
<script>
$(function () {
$('#go').on('click', function () {
$('#out').text('Sent…');
$.getJSON('https://jsonplaceholder.typicode.com/users/2')
.done(function (u) { $('#out').text('OK ' + u.username + ' — now inspect timing & headers'); })
.fail(function (x) { $('#out').text('fail ' + x.status); });
});
});
</script>
</body>
</html>
Run Example »
Edit the code below and click Run to see the result in Toolliyo’s live editor.
What happened?
- Check request payload on POST, response JSON, and CORS errors (often status 0).
- Compare waterfalls when widgets stampede.
- Preserve “Copy as cURL” for backend peers.
Practice next
- Open Network, click Fire XHR.
- Inspect status 200 and JSON.
- Break the URL and inspect 404.
- Enable Retain log across navigations.
- Throttle 3G to test spinners.
Remember
Network proves what shipped. Filter XHR. Copy as cURL for backends.
XHR autopsy
A Razorpay QueryVerse settlement refresh “works on my machine” but 401s in UAT.
Outcome: Network tab shows the missing auth cookie/header.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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