AJAX

1. AJAX

2. AJAX? AJAX – Asynchronous Javascript and XML • It is a technique involving JS/XML • Communication with a server HTTP in background • Client side logic that makes a web app experience more like a desktop app • Typically by manipulating the Document Object Model (DOM)

3. Fundamentals • Asynchronous - ? • Non-blocking request. Send request and continue doing what you do. Handle response whenever it comes • Typically ideal when request handled offsite (and you aren’t doing the work

4. Javascript C/Java like language No longer tied to Java, just in name Weakly typed – everything is just a var Modularity is weak … wat?

5. Example var map;function initialize(){varmapOptions={    zoom:8,    center:newgoogle.maps.LatLng(-34.397,150.644),mapTypeId:google.maps.MapTypeId.ROADMAP};  map =newgoogle.maps.Map(document.getElementById('map-canvas'),mapOptions);}google.maps.event.addDomListener(window,'load', initialize);

6. XML XML is the format of data exchange Request and Response is handled in XML which directly corresponds to DOM convention

7. HTTP • GET – Requests data from a specific resource • Can be cached • Can affect browser history (back button behavior) • Name/value pairs in the URL • POST – Submits data for processing in the HTTP body • Name/value pairs in the HTTP message itself • Heavier, typically slower, but cleaner (basically only advantage) • Good for binary data, large amounts of data

8. Example