How to Get File Size Before Uploading with AJAX and PHP?

Determining File Size Prior to Uploading Using AJAX/PHP

In the world of web applications, file uploading is a common task. Often, it's beneficial to determine the size of a file before initiating the upload process. This allows for validations and optimizations to enhance user experience.

Using a combination of AJAX and PHP, it's possible to retrieve the file size before uploading.

AJAX Solution

Leveraging the change event on the input file, you can utilize the following JavaScript snippet:

<code class="javascript">// Bind to onchange event of your input field
$('#myFile').bind('change', function() {
  // this.files[0].size gets the size of your file
  alert(this.files[0].size);
});</code>

This script will provide you with the file size in bytes, allowing for further processing before proceeding with the upload.

PHP Solution

On the PHP server side, you can access the file size using the $_FILES superglobal variable:

<code class="php">// Get the file size
$fileSize = $_FILES['myFile']['size'];</code>

This approach can be integrated into your PHP script to handle file size checks and perform necessary actions before uploading.

For more information and discussions related to this topic, refer to the following resources:

• How to check file input size with jQuery?

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