Key difference: AJAX stands for Asynchronous JavaScript and XML. It is a group of web development programs used to design websites. The programs create interactive web applications using a combination of XHTML for basic programming, CSS for styling, DOM for interaction, data exchange using XML and XSLT, XMLHttpRequest and JavaScript. Whereas, JavaScript is an interpreted computer programming language. It is a prototype-based scripting language that is dynamic, weakly typed, and has first-class functions. While embedding JavaScript on a webpage, it may appear almost anywhere within the HTML file.

AJAX stands for Asynchronous JavaScript and XML. It is a group of web development programs used to design websites. The programs create interactive web applications using a combination of XHTML for basic programming, CSS for styling, DOM for interaction, data exchange using XML and XSLT, XMLHttpRequest and JavaScript. AJAX enables web pages to send data to and receive data from a server without changing or hindering the web page itself. AJAX eliminates the need for the customers to wait, making interaction between the customer and the server asynchronous.

Google is the biggest known supporter of AJAX and has invested millions of dollars to advance it. Major Google products, such as Orkut, Gmail, Google Suggest, and Google Maps are AJAX applications. Amazon has also launched it’s own search engine, A9, on AJAX.

Ajax is not a single technology. It is a group of technologies. Jesse James Garrett, the one who coined the term, AJAX, lists the various technologies incorporated in AJAX:

• HTML (or XHTML) and CSS for presentation
• The Document Object Model (DOM) for dynamic display of and interaction with data
• XML for the interchange of data, and XSLT for its manipulation
• The XMLHttpRequest object for asynchronous communication
• JavaScript to bring these technologies together

Even though their names suggest that Java and JavaScript must be related somehow, it is just not true. JavaScript is an interpreted computer programming language. The main difference between Java and JavaScript is that while Java is a programming language, JavaScript is scripting language. It is a prototype-based scripting language that is dynamic, weakly typed, and has first-class functions. However, like Java, JavaScript is heavily influenced by the C programming language. JavaScript also borrows many names and naming conventions from Java, but it does have very different semantics than Java.

JavaScript takes its key design principles from the Self and Scheme programming languages. It is a multi-paradigm language that supports object-oriented, imperative, and functional programming styles.

JavaScript was formalized in the ECMAScript language standard and was originally implemented as part of web browsers. It allowed client-side scripts to interact with the user, control the browser, communicate asynchronously, and alter the document content that was displayed. However, JavaScript is also used in applications outside of web pages, such as in PDF documents, site-specific browsers, and desktop widgets. Furthermore, newer and faster JavaScript VMs and frameworks have also increased the popularity of JavaScript for server-side web applications.

There are various similarities between Java and JavaScript, such as both have a C-like syntax. They are both object-oriented and typically sandboxed, especially when used inside a browser. Also, JavaScript was designed with Java's syntax and standard library in mind. All Java keywords were reserved in original JavaScript. JavaScript's standard library follows Java's naming conventions, and JavaScript's Math and Date objects are based on classes from Java 1.0. However, they are much more different than they are similar.

The main difference between the two is that AJAX is a method to dynamically update parts of the UI without having to reload the page. It is a way to talk to the server in the background, while JavaScript is a language that the browser understands. Javascript is a client-side, i.e. in the browser scripting language.

Some differences between AJAX and JavaScript:

• AJAX sends request to the server and does not wait for the response. It performs other operations on the page during that time. Whereas, JavaScript makes a request to the server and waits for response.
• AJAX does not require the page to refresh for downloading the whole page, whereas JavaScript manages and controls a Web page after being downloaded.
• AJAX minimizes the overload on the server since the script needs to request once, while JavaScript posts a request that updates the script every time.
• AJAX is an approach towards page reloading, while JavaScript is a way to incorporate content on the webpage.
• AJAX allows the coder to send a request for data asynchronously in order to load new data without changing the web page.
• JavaScript allows the creation of dynamic webpages by providing a new level of interactivity.
• AJAX supports the server side scripting language, whereas JavaScript supports the client side scripting language.
• AJAX can load a webpage after it has been loaded for the first time. Whereas, JavaScript cannot reload the page after it is loaded.
• AJAX cannot be used to install a Trojan in the computer, while JavaScript can be used.

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