Ajax
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AJAX is a technique for building fast, interactive web applications. It uses a combination of XML, HTML, CSS, JavaScript, DOM, and XMLHttpRequest to retrieve data from the server asynchronously in the background without interfering with the display and behavior of the existing page. The XMLHttpRequest object plays a key role by sending and receiving data in the background from the web server. This allows parts of a web page to be updated without reloading the whole page.
Ajax
- 1. AJAX - Asynchronous JavaScript and XML Arulkumar Varatharajan – AP/CSE
- 2. AJAX AJAX new technique for creating better, faster, and more interactive web applications with the help of XML, HTML, CSS, and Java Script. 2 AJAX, is a web development technique for creating interactive web applications.
- 3. AJAX 3 AJAX, AJAX is based on the following open standards •Browser-based presentation using HTML and Cascading Style Sheets (CSS). •Data is stored in XML format and fetched from the server. •Behind-the-scenes data fetches using XMLHttpRequest objects in the browser. •JavaScript to make everything happen.
- 4. AJAX - XMLHttpRequest 4 AJAX, XMLHttpRequest (XHR) is an API that can be used by JavaScript, JScript, VBScript, and other web browser scripting languages to transfer and manipulate XML data to and from a webserver. It using HTTP, establishing an independent connection channel between a webpage's Client-Side and Server-Side.
- 5. AJAX - XMLHttpRequest 5 AJAX, The data returned from XMLHttpRequest calls will often be provided by back-end databases. Besides XML, XMLHttpRequest can be used to fetch data in other formats, e.g. JSON or even plain text.
- 6. How AJAX works? 6 AJAX communicates with the server using XMLHttpRequest object. Let's try to understand the flow of ajax or how ajax works by the image displayed below.
- 7. AJAX - XMLHttpRequest 7 AJAX, As you can see in the above example, XMLHttpRequest object plays a important role. -User sends a request from the UI and a javascript call goes to XMLHttpRequest object. -HTTP Request is sent to the server by XMLHttpRequest object. -Server interacts with the database using JSP, PHP, Servlet, ASP.net etc. -Data is retrieved. -Server sends XML data or JSON data to the XMLHttpRequest callback function. -HTML and CSS data is displayed on the browser.
- 8. XMLHttpRequest Methods- Call back 8 ▰abort()Cancels the current request ▰getAllResponseHeaders()Returns the complete set of HTTP headers as a string. ▰getResponseHeader( headerName )Returns the value of the specified HTTP header. ▰open( method, URL ) open( method, URL, async ) open( method, URL, async, userName ) open( method, URL, async, userName, password ) ▰The method parameter can have a value of "GET", "POST", or "HEAD". Other HTTP methods, such as "PUT" and "DELETE" (primarily used in REST applications) may be possible. ▰
- 9. XMLHttpRequest Methods- Call back 9 ▰send( content )Sends the request. ▰setRequestHeader( label, value ) Adds a label/value pair to the HTTP header to be sent.
- 10. XMLHttpRequest Properties 10 ▰Onreadystatechange An event handler for an event that fires at every state change. ▰readyState The readyState property defines the current state of the XMLHttpRequest object. ▰The following table provides a list of the possible values for the readyState property: ▰
- 11. 11 THANKS! Any questions? You can find me at @username & user@mail.me