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Introduction to developing web sites using PHP - Part 1 |
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When you use a web browser such as Firefox or Internet Explorer to access a web page, the contents of the web page (the text and images) are downloaded from the web server (where the page is stored) to the browser so that you can view the page. The web server is a piece of software that runs on a computer. The location of this computer may be in the same country as you're in, or it may be in another country. Static web pagesWhen people began creating web sites in the mid-1990s, all web pages were what is now known as 'static' pages. A static web page is one whose contents are the same everytime it is downloaded to a browser, unless the page is manually updated by a web designer/developer. Dynamic web pagesGradually, as technologies and languages progressed, people developing web pages were able to make the web pages change slightly when they were being viewed, for example, the date might be displayed on the web page, or the buttons on the page might change when the mouse pointer is passed over them. These pages were early versions of what we now call 'dynamic' web pages. Client-side and server-side scripting languagesIn the early days, dynamic content was created using client-side scripting languages such as JavaScript (which is still used extensively today). A client-side script gets downloaded to a browser when a web page (that uses the script) is downloaded. The script then runs in the browser, which in turn is running on the client computer, which is why it is called a client-side script. Server-side scripting languages run on the computer (server) where the web pages are stored. The script itself is not downloaded to the browser, although the content or results that are generated when the script is run may well be downloaded. Typically, a server-side script communicates with a database, which generates content that is downloaded to the browser. As this content will vary depending on, for example, the search criteria used in order to extract data from the database, the pages are dynamically generated and will be different for different search criteria. PHPPHP is a server-side scripting language. It was originally created by Rasmus Lerdorf in 1995, although the main implementation of PHP is now produced by The PHP Group and serves as the de facto standard for PHP as there is no formal specification. Released under the PHP License, the Free Software Foundation considers it to be free software. Go back to PHP Tutorials home page Go back to Tutorials home page
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