Steven Holzner, “AJAX: A Beginner’s Guide” 2008 | pages: 494 | ISBN: 0071494294 | PDF | 11,3 mb. Designed for Easy Learning: Key Skills & Concepts–Lists of. Get this from a library! Ajax : a beginner's guide. [Steven Holzner] -- This book offers an easy way to learn AJAX. New to the bestselling 'Beginner's Guide' series. 12 Responses to “Beginner’s Guide to Ajax Development with PHP” Chris on November 13, 2013 at 7:50 am said: Excellent tutorial. Ajax Tutorial for Beginners: Part 1; Author: bhupiyujuan; Updated:; Section: Ajax; Chapter: Web Development; Updated. It provides more than 100 UI Components and an in-built AJAX support. PrimeFaces Beginners Guide is a practical. With this PrimeFaces Beginner’s Guide. Ajax for Beginners - Webmonkey. Java. Script has had the XMLHttp. Request object for almost a decade now, but it really only started getting wide attention in 2. All this attention was mostly due to some showoff web applications that made every developer who saw them think, “I want my site to do that!” But it also has to do with the spiffy, spiffy name given to it by the folks at Adaptive. Path, who named this asynchronized application Ajax. Maybe you’ve heard of it? A few high- profile Google applications in particular made a splash with Ajax: Maps and Gmail were first. It also powers some of the core functionality in the user interface of the ever- so- popular photo sharing site Flickr. By now, Ajax has become integral to the fabric of the web, especially in the era of real- time applications like Twitter, Buzz and Wave (all of which use Ajax extensively in their webapp front ends, for the record). Ajax may also lay claim to being the first Java. Script object with its own fan website. Date. com doesn’t count, although I did have a scintillating chat with a lady there once about the get. Introduction. Hello readers this is my first effort to write here it is focused to help the beginners who are looking to start working with ASP.Net AJAX. Please send 1.Ajax A Beginner’s Guide pdf book to this below email-id [email protected]. Reply Delete. Time. Zoneoffset method. What is Ajax? So what is this fancy object that everybody wants a piece of? In brief, it’s a solution to one of the big annoyances of web interfaces. Generally, the user inputs some data or makes a choice, and clicks a button that sends the data to the server. The server takes a look at the data and sends back a whole new web page, which is loaded into the browser. Reloading a page every time you want to do something is annoying, disjunctive and time- consuming for the user. XMLHttp. Request moves that browser- server interaction to behind the scenes, so the user can just keep on playing with the same page, even while elements on the page are talking to the server! Go take a look at Google Suggest if I’ve lost you — it’s a nice, eloquent example of this. Java. Script has always been able to sneakily trigger a server- side script without anything happening in the browser by using a few classic tricks. This one, for example: on. Submit='runascript = new Image(); runascript. That sort of chicanery is good, maybe, for caching form data to a file on the server, but it doesn’t return any information to the Java. Script that calls it, so its usefulness is limited. Ajax, on the other hand, can get a full parcel of data back from the script it calls. Hence the “XML” part of the name – which really is just there for looks, kind of like the “Java” part of Java. Script, because the returned data can be plain text or whatever you like, if XML is overkill or just not your cup of tea. This opens up millions of exciting possibilities. Every form submission, every Java. Script event, and heaven knows what else, can now interact with server- side databases and processing power. Data retrieval, password authentication, image generation – you name it, Ajax can trigger it. Making Your Own. The potential of Ajax- enhanced web apps is limited only by your imagination – and by browser support. Mozilla- based browsers can do it, and Safari, and newer versions of Explorer, and Opera 8 but not Opera 7. It’s best to incorporate a fallback way of doing things for users who aren’t as cutting edge as you’d like them to be. Also, Explorer does things somewhat differently (of course) from all the other browsers, so it’s necessary to fork the code to account for the irritating little 8. IE. Let’s build a simple application that accepts input from the user, passes it to some PHP on the server that checks it against a database, and returns the result to the browser. It comes in three parts. First, we need an HTML form. This you’ve seen before. Report< /title>. Welcome, student. Please enter your essay here: < textarea name="essay" id="essay">. Submit" on. Click="return. Note that, for users without support for our script (named xhr. Next comes the Java. Script. This is the exciting part, so we’ll take it slow. First, we initialize the object. We have to do it two ways, for different browsers. Mozilla version. if (window. XMLHttp. Request) {. XMLHttp. Request(). IE version. else if (window. Active. XObject) {. Active. XObject("Microsoft. XMLHTTP"). Then, we escape the user input to make it URL- safe. URIComponent(essay). PHP script. xhr. open("POST","grade. The method requires two arguments: first, the HTTP method (GET or POST); second, the URL of the script. A quick HTTP header prepares the script for what it’s getting, and then the send method transmits the actual request. Request. Header(. Content- Type'. 'application/x- www- form- urlencoded; charset=UTF- 8'); xhr. This last step isn’t necessary for GET requests, wherein all the data can be contained in the query string of the URL. Getting Results. Now we’re ready to see if the HTTP request worked. The ready. State property counts up from zero during the request, and shows 4 when the server page has loaded successfully. State==4) {. If the request worked, then we can get the output of the server- side script by querying the response. Text property, which contains a string. For more complex server script output, a response. XML property, which can hold a full document object of XML data, is also available. Text. alert ("Nice essay. Your grade is " + grade). Want to see all that in a pastable block? Here it is in a separate file. Finally, the third component is the PHP script, which lives on the server and waits patiently for the Java. Script to pass it some juicy data. This example uses PHP, but any language you like — Ruby, Perl, C, ASP — can do as well. The core of this example script is a natural- language function called grade_essay() that grades student essays from 1 to 1. I will redact that part to conserve space. The php: //input grabs the POST data, which gets put into a string, decoded and passed to the ingenious grading algorithm. The algorithm returns a numeric grade. Lastly, we just output the grade with echo – ordinarily, this would display in the browser, but since the PHP script is running “behind the scenes,” the string output is simply returned to the Java. Script that called it. If you need structured data, an XML document would be output with an echo statement in just the same way, but the content- type of the output page must be set to text/xml. What the user sees is this: She types her essay into the text area in the browser, clicks Submit, and within instants an alert box pops up giving her a final grade on the essay. Invisibly, the essay has been sent to the server, read and evaluated by a team of PHP gnomes, and returned with a grade, without ever reloading the page. The user can modify her essay and resubmit it endlessly. And that’s the gist of the almost magical XMLHttp. Request object! The example is simple, but the uses of the object can be elaborately, multifariously clever. If you need further inspiration and edification, a burgeoning number of examples are dotted around the Web. But what data you send and receive with Ajax is up to you. Ajax Tutorial for Beginners: Part 1. Introduction. Hello everyone. This is my first article on The Code Project. I hope you will get some benefit from it. I have been learning Ajax for the last 5 months and now I want to share my knowledge with you. Please provide feedback on any mistakes which I have made in this article. Believe me guys, your harsh words would be received with love and treated with the top most priority. I have explained Ajax with XML and JSON in part 2, which you can read here. There are many books and articles out there explaining the 5 Ws (Who, What, Where, When, Why) of Ajax, but I will explain to you in my own simple way. So what is Ajax? The term AJAX (Asynchronous Java. Script and XML) has been around for three years created by Jesse James Garrett in 2. The technologies that make Ajax work, however, have been around for almost a decade. Ajax makes it possible to update a page without a refresh. Using Ajax, we can refresh a particular DOM object without refreshing the full page. Background of Ajax. In Jesse Garrett’s original article that coined the term, it was AJAX. The “X” in AJAX really stands for XMLHttp. Request though, and not XML. Jesse later conceded that Ajax should be a word and not an acronym and updated his article to reflect his change in heart. So “Ajax” is the correct casing. As its name implies, Ajax relies primarily on two technologies to work: Java. Script and the XMLHttp. Request. Standardization of the browser DOM (Document Object Model) and DHTML also play an important part in Ajax’s success, but for the purposes of our discussion we won't examine these technologies in depth. How Ajax Works. At the heart of Ajax is the ability to communicate with a Web server asynchronously without taking away the user’s ability to interact with the page. The XMLHttp. Request is what makes this possible. Ajax makes it possible to update a page without a refresh. By Ajax, we can refresh a particular DOM object without refreshing the full page. Let's see now what actually happens when a user submits a request: Web browser requests for the content of just the part of the page that it needs. Web server analyzes the received request and builds up an XML message which is then sent back to the Web browser. After the Web browser receives the XML message, it parses the message in order to update the content of that part of the page. AJAX uses Java. Script language through HTTP protocol to send/receive XML messages asynchronously to/from Web server. Asynchronously means that data is not sent in a sequence. Common Steps that AJAX Application Follows. The figure below describes the structure of HTML pages and a sequence of actions in Ajax Web application: The Java. Script function hand. Event() will be invoked when an event occurred on the HTML element. In the hand. Event() method, an instance of XMLHttp. Request object is created. The XMLHttp. Request object organizes an XML message within about the status of the HTML page, and then sends it to the Web server. After sending the request, the XMLHttp. Request object listens to the message from the Web server. The XMLHttp. Request object parses the message returned from the Web server and updates it into the DOM object. Let's See How Ajax Works in the Code. Let’s start to put these ideas together in some code examples. Time". input type="button" id="btn. Get. Time" value="Get Time" onclick="Get. Time(); ". form. From the above code, our DOM object is (input type="text" id="lbl. Time") which we have to refresh without refreshing the whole page. This will be done when we press the event of a button, i. In this code, our hand. Event() is Get. Time() from the above Figure- 2 if you take a look at it. Let's see now how we create an Xml. Http. Request object and make Ajax work for us. The basic implementation of the XMLHttp. Request in Java. Script looks like this: var xml. Http. Request. function Get. Time(). xml. Http. Request = (window. XMLHttp. Request) ? XMLHttp. Request() : new Active. XObject("Msxml. 2. XMLHTTP"). if (xml. Http. Request == null). Http. Request. open("GET", "Time. Http. Request. onreadystatechange = State. Change. xml. Http. Request. send(null). State. Change(). if(xml. Http. Request. ready. State == 4). document. Element. By. Id('lbl. Time'). value = xml. Http. Request. response. Text. }Now from the above Figure- 2 hand. Event() i. e. Get. Time() creates an XMLHttp. Request object inside it like this: //create XMLHttp. Request object. xml. Http. Request = (window. XMLHttp. Request) ? XMLHttp. Request() : new Active. XObject("Msxml. 2. XMLHTTP"); If the browser does not support Ajax, it will return false. Next we open our connection to the server with our newly created XMLHttp. Request object. Here the Time. XML message that is stored on the Web server.//Initiate the XMLHttp. Request object. xml. Http. Request. open("GET", "Time. You often hear the term “callback” replace the term “postback” when you work with Ajax. That’s because Ajax uses a “callback” function to catch the server’s response when it is done processing your Ajax request. We establish a reference to that callback function like this. Here State. Change is a function where we update or set a new value to our DOM object, i. Time".//Setup the callback function. Http. Request. onreadystatechange = State. Change; Let's have a look at our callback function: function State. Change(). if(xml. Http. Request. ready. State == 4). document. Element. By. Id('lbl. Time'). value = xml. Http. Request. response. Text. }onreadystatechange will fire multiple times during an Ajax request, so we must evaluate the XMLHttp. Request’s “ready. State” property to determine when the server response is complete which is 4. Now if ready. State is 4, we can update the DOM object with the response message we get from the Web server. As the request method we are sending is "GET" (remember it is case sensitive), there is no need to send any extra information to the server. Send the Ajax request to the server with the GET data. Http. Request. send(null); In Time. Page_Load event, write a simple response like this which is our response message: Response. Write( Date. Time. Now. Hour + ": " + Date. Time. Now. Minute +. Date. Time. Now. Second ); That’s it. That’s Ajax. Really. Key Points to be Remembered in Ajax. There are three key points in creating an Ajax application, which are also applicable to the above Tutorial: Use XMLHttp. Request object to send XML message to the Web server Create a service that runs on Web server to respond to request Parse XMLHttp. Request object, then update to DOM object of the HTML page on client- side History. November, 2. 00. 8: Initial version Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.
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