


Displaying a Progress Bar While Loading Data with AJAX
When performing an AJAX query that retrieves data from a database, it can take some time for the results to be returned. To provide feedback to the user during this loading process, a progress bar can be displayed.
Creating a Progress Bar with jQuery
The jQuery library offers built-in methods that facilitate the creation and manipulation of progress bars. To add a progress bar to your AJAX call, you can attach an event listener to the xhr object:
<code class="javascript">$.ajax({ xhr: function() { var xhr = new window.XMLHttpRequest(); // Upload progress xhr.upload.addEventListener("progress", function(evt) { if (evt.lengthComputable) { var percentComplete = evt.loaded / evt.total; // Update the progress bar here } }, false); // Download progress xhr.addEventListener("progress", function(evt) { if (evt.lengthComputable) { var percentComplete = evt.loaded / evt.total; // Update the progress bar here } }, false); return xhr; }, type: 'POST', url: "/", data: {}, success: function(data) { // Hide the progress bar and display the results } });</code>
In this code:
- The progress event listener for the upload property tracks the progress of sending data to the server.
- The progress event listener for the xhr object tracks the progress of receiving data from the server.
- You can use the percentComplete variable to determine the completion percentage and update the progress bar accordingly.
- After the data has been successfully retrieved and processed, the progress bar can be hidden and the results can be displayed.
By implementing this approach, you can enhance your AJAX callbacks with a user-friendly progress bar, providing visual feedback during data loading operations.
The above is the detailed content of How to Display a Progress Bar During AJAX Data Loading with jQuery?. For more information, please follow other related articles on the PHP Chinese website!

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