A Real-World Ajax Application in Font

Printer ECC200 in Font A Real-World Ajax Application

CHAPTER
Painting Data Matrix ECC200 In None
Using Barcode generation for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
Printing Code128 In None
Using Barcode printer for Font Control to generate, create Code 128 Code Set B image in Font applications.
www.OnBarcode.com
A Real-World Ajax Application
GTIN - 13 Drawer In None
Using Barcode creator for Font Control to generate, create GS1 - 13 image in Font applications.
www.OnBarcode.com
Denso QR Bar Code Printer In None
Using Barcode drawer for Font Control to generate, create QR-Code image in Font applications.
www.OnBarcode.com
n order to obtain a complete understanding of what goes into making Ajax-based applications, it makes sense that you should build one from scratch. In order to illustrate that process, I will lead you through the process of creating an Ajax-based photo gallery. The photo gallery is a fairly common web application that is popular among professional web developers and hobbyists alike. The problem with something like a photo gallery is that it has all been done before. Therefore, when envisioning what I wanted to do with a photo gallery, I brainstormed features that I would like to see implemented whenever I deploy a photo gallery, and ways to make the gallery look different than the majority of gallery-based applications currently on the Internet. The last aspect I considered is how to improve upon commonplace photo gallery code by using Ajax concepts. There are definitely cases in which using Ajax does more harm than good (examples of such can be found in 11), and so I wanted something that would improve upon the common gallery-viewing (and gallery-maintaining) functionality. I wanted this gallery to remove most of the tedium otherwise involved in uploading images. I find that it is time-consuming to maintain and upload images to most galleries (the less robust ones, anyway). I wanted something I could quickly insert images into without having to worry about resizing them. I also really like the idea of seeing the thumbnails of upcoming images before you click on them (like what you see on MSN Spaces). That makes it more interesting to view the gallery. Since I am really against the whole uploading thing, I also set up the system so that you can simply drop a big batch of images straight into the images directory, and the system will simply read through the directory and build the structure straight from that. If you were really interested in keeping more information on the files, it wouldn t be too difficult to categorize them with subfolders and use their files name for captions. I also did not want any page refreshing. It is quite likely that I would plug this gallery system into a more robust application, and I didn t want to load the rest of the application every time I wanted to upload a new image or check out the next one. Therefore, I turned to JavaScript and Ajax to provide the required functionality.
UPC Symbol Creation In None
Using Barcode maker for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
Encoding Code 3 Of 9 In None
Using Barcode drawer for Font Control to generate, create ANSI/AIM Code 39 image in Font applications.
www.OnBarcode.com
CHAPTER 7 A REAL-WORLD AJAX APPLICATION
Draw EAN / UCC - 13 In None
Using Barcode generator for Font Control to generate, create GTIN - 128 image in Font applications.
www.OnBarcode.com
International Standard Serial Number Drawer In None
Using Barcode creator for Font Control to generate, create ISSN image in Font applications.
www.OnBarcode.com
The Code
Reading Data Matrix In VS .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Generating Data Matrix In .NET
Using Barcode drawer for ASP.NET Control to generate, create ECC200 image in ASP.NET applications.
www.OnBarcode.com
Let s now take a look at the code that makes up the application. First, Listing 7-1 is the main script to be loaded in the browser. Everything runs through this script. Listing 7-2 shows the JavaScript code that is used, including running Ajax requests and updating the user interface. The remainder of the listings (7-3 through 7-7) covers the various PHP code required to display forms, process uploads, and output images. After these listings, we will look more closely at the code to see how it all works and to see the results it produces.
Reading Code 128A In .NET Framework
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Code 128 Code Set B Generation In Objective-C
Using Barcode creator for iPhone Control to generate, create Code 128 image in iPhone applications.
www.OnBarcode.com
Listing 7-1. The HTML Shell for the Photo Gallery (sample7_1.php)
ECC200 Scanner In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Read Barcode In Visual C#
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in .NET applications.
www.OnBarcode.com
<!-- sample7_1.php --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <link rel="stylesheet" type="text/css" href="style.css" /> <title>Sample 7_1</title> <script type="text/javascript" src="functions.js"></script> </head> <body> <h1>My Gallery</h1> <div id="maindiv"> <!-- Big Image --> <div id="middiv"> < php require_once ("midpic.php"); > </div> <!-- Messages --> <div id="errordiv"></div> <!-- Image navigation --> <div id="picdiv">< php require_once ("picnav.php"); ></div> </div> <h2>Add An Image</h2> <form action="process_upload.php" method="post" target="uploadframe" enctype="multipart/form-data" onsubmit="uploadimg(this); return false">
Drawing Code 128 Code Set B In Java
Using Barcode generation for Android Control to generate, create ANSI/AIM Code 128 image in Android applications.
www.OnBarcode.com
Draw Barcode In Visual Studio .NET
Using Barcode drawer for .NET Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
CHAPTER 7 A REAL-WORLD AJAX APPLICATION
Barcode Reader In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
www.OnBarcode.com
Barcode Reader In .NET
Using Barcode scanner for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
<input type="file" id="myfile" name="myfile" /> <input type="submit" value="Submit" /> <iframe id="uploadframe" name="uploadframe" src="process_upload.php"> </iframe> </form> </body> </html>
Generate PDF417 In Java
Using Barcode creator for Java Control to generate, create PDF 417 image in Java applications.
www.OnBarcode.com
Print Code 128 In Objective-C
Using Barcode creator for iPad Control to generate, create Code 128 Code Set C image in iPad applications.
www.OnBarcode.com
Listing 7-2. The JavaScript Required to Make the Gallery Run (functions.js)
// functions.js function runajax(objID, serverPage) { //Create a boolean variable to check for a valid Internet Explorer instance. var xmlhttp = false; //Check if we are using IE. try { //If the JavaScript version is greater than 5. xmlhttp = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { //If not, then use the older ActiveX object. try { //If we are using Internet Explorer. xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } catch (E) { //Else we must be using a non-IE browser. xmlhttp = false; } } // If we are not using IE, create a JavaScript instance of the object. if (!xmlhttp && typeof XMLHttpRequest != 'undefined') { xmlhttp = new XMLHttpRequest(); } var obj = document.getElementById(objID); xmlhttp.open("GET", serverPage); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
Copyright © OnBarcode.com . All rights reserved.