We need a PHP script to process form submissions because when you submit a form on a website, the information you enter and the files you upload, needs to be processed and handled in some way. For example, it might need to be saved to a database, or sent to someone via email. PHP is a server-side programming language, which means it runs on the web server rather than in your web browser.
In Web applications, the common way of uploading files to a web server is through the submission of a form. However, you might come into some scenarios where you might need to upload files via Ajax. This tutorial will show you how. The following list shows the browser support for Ajax. Opera 7.6 and above. Mozilla Firefox 1.0 and above. Apple Safari 1.2 and above. Netscape version 7.1 and above. Microsoft Internet Explorer 5 and above.