jQuery .ajaxStart() Method

Posted in jQuery Tutorial

Updated on May 14, 2024

By Mari Selvan

👁️ 21 - Views

⏳ 4 mins

💬 0

Photo Credit to CodeToFun

🙋 Introduction

jQuery offers a wide range of methods to manage and manipulate AJAX (Asynchronous JavaScript and XML) operations seamlessly. One such method is ajaxStart, which is a global event handler that triggers whenever an AJAX request starts. This can be particularly useful for providing feedback to users, such as showing a loading spinner.

In this guide, we'll explore the ajaxStart method, its usage, and practical examples to help you leverage this functionality effectively.

🧠 Understanding .ajaxStart() Method

The ajaxStart method is part of jQuery's AJAX event handling system. It is triggered whenever an AJAX request is initiated, providing a convenient hook to execute code before the request is sent. This method is often used to show indicators that a background operation is in progress.

💡 Syntax

The syntax for the .ajaxStart() method is straightforward:

syntax.js

Copied

$(document).ajaxStart(function() {
    // Code to run when an AJAX request starts
});

📝 Example

Showing a Loading Spinner:

A common use case for ajaxStart is to display a loading spinner when an AJAX request is in progress. Here's an example:
index.html
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```
<div id="loading" style="display:none;">Loading...</div>
```
example.js
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```
$(document).ajaxStart(function() {
  $("#loading").show();
}).ajaxStop(function() {
  $("#loading").hide();
});
```
In this example, the #loading element is shown when an AJAX request starts and hidden when the request completes.
Disabling Form Submission:

You can use ajaxStart to disable a form's submit button while an AJAX request is in progress, preventing multiple submissions:
index.html
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```
<form id="myForm">
  <input type="text" name="data">
  <button type="submit" id="submitBtn">Submit</button>
</form>
```
example.js
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```
$(document).ajaxStart(function() {
  $("#submitBtn").prop("disabled", true);
}).ajaxStop(function() {
  $("#submitBtn").prop("disabled", false);
});
```
This ensures that the submit button is disabled during the AJAX request and re-enabled once the request completes.
Combining with Other AJAX Events:

You can combine ajaxStart with other AJAX event handlers like ajaxStop, ajaxError, and ajaxSuccess for more comprehensive AJAX request handling:
example.js
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```
$(document).ajaxStart(function() {
  $("#loading").show();
}).ajaxStop(function() {
  $("#loading").hide();
}).ajaxError(function(event, jqxhr, settings, thrownError) {
  alert("An error occurred: " + thrownError);
});
```
This example shows a loading indicator during the request and handles errors by displaying an alert.
Handling Multiple AJAX Requests:

If your application makes multiple AJAX requests, ajaxStart will trigger at the start of each request. To avoid repetitive actions, ensure that your handling logic accounts for multiple requests:
example.js
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```
$(document).ajaxStart(function() {
  if ($(".loading-indicator").length === 0) {
      $("body").append('<div class="loading-indicator">Loading...</div>');
  }
}).ajaxStop(function() {
  $(".loading-indicator").remove();
});
```
This ensures that only one loading indicator is shown regardless of the number of AJAX requests.

🎉 Conclusion

The jQuery ajaxStart method is a powerful tool for managing AJAX request states, allowing you to provide real-time feedback to users. By mastering its usage, you can enhance user experience by showing loading indicators, preventing multiple submissions, and handling errors gracefully.

Incorporate the ajaxStart method into your projects to create more interactive and responsive web applications.