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AJAX MIS 424 Professor Sandvig Today 1. What is AJAX 2. Benefits & Uses 3. Implementation 1. 2. 3. Do-it-yourself Download API ASP.NET Ajax 4. Summary What is AJAX Acronym Asynchronous JavaScript And XML What it is JavaScript in web page retrieves data from server Data format is XML Allows partial page refresh Reduces need to refresh entire page What is AJAX Data format does not need to be XML Depends upon audience Popular formats: JSON Text XML CSV Custom Benefits & Uses Benefits: Richer experience for user More like using desktop application Uses Google Suggest (JSON) Kelly Blue Book (Cascading Menus) (JSON) REI product image (menu) (JSON) Google Maps (blob) Amazon (wishlist) (JSON) MIS 314 bookstore (HTML) etc. etc. Implementation Options: 1. Do-it-yourself 2. Lightweight, flexible write or modify JavaScript or jQuery Use API 1. 3. Google, Yahoo, Highslide, … ASP.NET AJAX drag & drop in VS convenient adds a lot of code to application Do it yourself Client Include JavaScript or jQuery in web page Requests data from server Server Web service provides data Format: XML, JSON, HTML, … Do it yourself Benefits Flexible Lightweight Drawbacks Time consuming Some knowledge of JavaScript/jQuery Do it Yourself Examples XML JavaScript Jquery ZipCodesForCity.asmx (same .asmx) AjaxZipCode.aspx AJAXZipCode.aspx HTML Bookstore JSON AjaxZipCode Home grown CarParts.com Use AJAX API Ajax applications written by others Google AJAX APIs Search Maps Calendar Facebook APIs ASP.NET AJAX ASP.NET provides built-in AJAX functionality Two flavors: Built into some Data Controls Limitations ScriptManager & Update Panel Very flexible Server Controls Built in AJAX functionality GridView, DetailsView, FormView Property: AllowSortingAndPagingCallbacks Benefits Easy to implement Limitations: Controls cannot use templates Inefficient: retrieves all data and discards extra UpdatePanel UpdatePanel Wrap any server controls Become AJAX enabled Benefits Easy to implement Flexibility Mix & match controls Specify triggers Update Panel Disadvantage JavaScript cannot be tweaked Fine if it meets your needs Heavy All controls are repopulated Viewstate also sent/received Example: Cascading Dropdown: AjaxAspNet.aspx Summary AJAX Use to improve user experience Partial page refreshes Options: 1. 2. 3. Code you own Use APIs ASP.NET AJAX