AJAX vs. PHP
Asynchronous JavaScript XML (or AJAX) is a group of interrelated web development techniques. They are used client-side to create interactive web applications. AJAX allows web applications to retrieve data from the server asynchronously in the background (meaning using an input/output process that allows other processing to continue before the transmission has finished). It does this without interfering with the display and behaviour of the existing page.
Hypertext Processor (or PHP) is a general purpose scripting language that was designed to produce dynamic web pages. It has the capability to be embedded in HTML pages and usually runs on a web server. It also has the capability to deploy on most web servers on almost every operating system and platform –which is free of charge for every user.
AJAX is not a stand alone technology, per se. Rather it is a group of technologies using a combination of components that include HTML and CSS for markup and styling information, DOM accessed with JavaScript to display and interact with the presented information, a method of exchanging data asynchronously between browser and server (to avoid page reloads), and a format for the data that is sent to said browser (such as XML, pre-formatted HTML, plain text, and JavaScript Object Notation –also known as JSON). AJAX does have its share of flaws. For instance, AJAX interfaces are markedly more difficult to develop on static pages. Dynamic web page updates also make it difficult for users to bookmark the application in certain states. More devastatingly, however, is the fact that any user’s browser that does not support JavaScript or XMLHttpRequest (or is functionally disabled) will not be able to run applications that depend on AJAX.
PHP was designed specifically for web development. Any PHP code is executed through the PHP runtime and generally used to create dynamic web page content. It also can function as command-line scripting and client-side GUI applications. The language acts as a filter to take input from a file or stream that contains text and/or PHP instructions and outputs a different stream of data (most commonly of the HTML format). However, there have been substantial levels of vulnerabilities in the PHP security (last charted at 35% in 2008). Such vulnerabilities can be remotely exploited, allowing hackers to steal and/or destroy data from data sources linked to the web server.
Summary:
1. AJAX is a group of technologies that allows web applications to retrieve data from the server asynchronously; PHP is a scripting language designed to produce dynamic web pages.
2. AJAX interfaces are difficult to develop on static pages and will not run applications on browsers that do not support JavaScript or XMLHttpRequest; PHP has a relatively high percentage of vulnerabilities, raising the level of hacker activity on data linked to a web server.