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PHP and AJAX. Servers and Clients. For many years we tried to move as much as possible to the server. Weak clients, poor bandwidth, browser compatibility.. Created a certain way of interacting with a website. Request – Response model. Clients and Servers.
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Servers and Clients • For many years we tried to move as much as possible to the server. • Weak clients, poor bandwidth, browser compatibility.. • Created a certain way of interacting with a website. • Request – Response model.
Clients and Servers • Client machines have become much more powerful. • You’re not using much of your duel core processor rendering a webpage • Bandwidth has increased dramatically • 9.5 million broadband users in the UK (2006, BBC) • “Broadband now makes up 57.4% of all net connections compared to 42.6% for dial-up. In the last year dial-up connections had shrunk by 28.7%” (2005, BBC) • 14,520,988 Q2 2007 (http://www.thinkbroadband.com/news/3280-number-of-uk-broadband-users-nearing-saturation-point.html)
Clients and Servers • Browsers now run JavaScript in a more predictable manner. • So the technology is ready for AJAX but what is it?
What isn't AJAX • A Language • A Technology • A Plug-in • Proprietary • All that hard • The answer to all of our dreams
What is AJAX? • Asynchronous JavaScript and XML • What is asynchronous? • Uses JavaScript and XML to create seamless interaction on a website. • Lots of CSS sites look ‘real purty’ but still have the response/request model of interaction. • Using Obvious forms for their interaction.
AJAX • “It uses the JavaScript XMLHttpRequest function to create a tunnel from the client's browser to the server and transmit information back and forth without having to refresh the page.” http://coldfusion.sys-con.com/read/138966.htm • Ajax has become synonymous with any rich web application or Web 2.0 / 3.0 application.
PHP and Ajax • XMLHttpRequest Object • “XMLHttpRequest (XHR) is an API that can be used by JavaScript, and other web browser scripting languages to transfer XML and other text data to and from a web server using HTTP, by establishing an independent communication channel between a web page's Client-Side and Server-Side.” - Wiki • Created in IE: var AlsAjaxObject = new ActiveXObject("Microsoft.XMLHTTP"); • In other browsers: var AlsAjaxObject = new XMLHttpRequest();
Demos • Image Editor • Text Stuff • Google Suggests • Google Maps
Some tutorials • http://www.w3schools.com/php/php_ajax_database.asp • http://www.ibm.com/developerworks/xml/library/os-php-rad1/ • http://www.phpbuilder.com/columns/kassemi20050606.php3 • http://www.phpbuilder.com/columns/kassemi20050606.php3 • http://www.johnwiseman.ca/blogging/tutorials/creating-a-mysql-connection-with-phpajax/
Links – Further Reading • http://dhtmlnirvana.com/ajax/ajax_tutorial/ • http://ajaxpatterns.org/wiki/index.php?title=Whats_Ajax • http://www.maxkiesler.com/index.php/weblog/comments/round_up_of_50_ajax_toolkits_and_frameworks/ • http://www.ajaxwith.com/PHP • http://www.fiftyfoureleven.com/resources/programming/xmlhttprequest/examples