JAVASCRIPT
What is JAVASCRIPT
JavaScript is a dynamic computer programming language. It is lightweight and most commonly used as a part of web pages, whose implementations allow client-side script to interact with the user and make dynamic pages. It is an interpreted programming language with object-oriented capabilities.
JavaScript was first known as LiveScript, but Netscape changed its name to JavaScript, possibly because of the excitement being generated by Java. JavaScript made its first appearance in Netscape 2.0 in 1995 with the name LiveScript. The general-purpose core of the language has been embedded in Netscape, Internet Explorer, and other web browsers.
The ECMA-262 Specification defined a standard version of the core JavaScript language.
- JavaScript is a lightweight, interpreted programming language.
- Designed for creating network-centric applications.
- Complementary to and integrated with Java.
- Complementary to and integrated with HTML.
- Open and cross-platform
Client-Side JavaScript
Client-side JavaScript is the most common form of the language. The script should be included in or referenced by an HTML document for the code to be interpreted by the browser.
It means that a web page need not be a static HTML, but can include programs that interact with the user, control the browser, and dynamically create HTML content.
The JavaScript client-side mechanism provides many advantages over traditional CGI server-side scripts. For example, you might use JavaScript to check if the user has entered a valid e-mail address in a form field.
The JavaScript code is executed when the user submits the form, and only if all the entries are valid, they would be submitted to the Web Server.
JavaScript can be used to trap user-initiated events such as button clicks, link navigation, and other actions that the user initiates explicitly or implicitly.
Advantages of JavaScript
The merits of using JavaScript are −
- Less server interaction − You can validate user input before sending the page off to the server. This saves server traffic, which means less load on your server.
- Immediate feedback to the visitors − They don’t have to wait for a page reload to see if they have forgotten to enter something.
- Increased interactivity − You can create interfaces that react when the user hovers over them with a mouse or activates them via the keyboard.
- Richer interfaces − You can use JavaScript to include such items as drag-and-drop components and sliders to give a Rich Interface to your site visitors.
Limitations of JavaScript
We cannot treat JavaScript as a full-fledged programming language. It lacks the following important features −
- Client-side JavaScript does not allow the reading or writing of files. This has been kept for security reason.
- JavaScript cannot be used for networking applications because there is no such support available.
- JavaScript doesn’t have any multi-threading or multiprocessor capabilities.
Once again, JavaScript is a lightweight, interpreted programming language that allows you to build interactivity into otherwise static HTML pages.
JavaScript Development Tools
One of major strengths of JavaScript is that it does not require expensive development tools. You can start with a simple text editor such as Notepad. Since it is an interpreted language inside the context of a web browser, you don’t even need to buy a compiler.
To make our life simpler, various vendors have come up with very nice JavaScript editing tools. Some of them are listed here −
- Microsoft FrontPage − Microsoft has developed a popular HTML editor called FrontPage. FrontPage also provides web developers with a number of JavaScript tools to assist in the creation of interactive websites.
- Macromedia Dreamweaver MX − Macromedia Dreamweaver MX is a very popular HTML and JavaScript editor in the professional web development crowd. It provides several handy prebuilt JavaScript components, integrates well with databases, and conforms to new standards such as XHTML and XML.
- Macromedia HomeSite 5 − HomeSite 5 is a well-liked HTML and JavaScript editor from Macromedia that can be used to manage personal websites effectively.
Where is JavaScript Today ?
The ECMAScript Edition 5 standard will be the first update to be released in over four years. JavaScript 2.0 conforms to Edition 5 of the ECMAScript standard, and the difference between the two is extremely minor.
Today, Netscape’s JavaScript and Microsoft’s JScript conform to the ECMAScript standard, although both the languages still support the features that are not a part of the standard.
JavaScript Frameworks
One major reason for the popularity of JavaScript is the JavaScript Frameworks. Here’s a brief introduction of the most trending JavaScript frameworks :
1. AngularJS is Google’s web development framework which provides a set of modern development and design features for rapid application development.
2. ReactJS is another top JavaScript framework mainly maintained by Facebook and it’s behind the User Interface of Facebook and Instagram, showing off its efficiency in maintaining such high traffic applications.
3. MeteorJS is mainly used for providing back-end development. Using JavaScript on the back-end to save time and build expertise is one of the major ideas behind Meteor.
4. jQuery can be used when you want to extend your website and make it more interactive. Companies like Google, WordPress and IBM rely on jQuery.
JavaScript Fundamentals
In this What is JavaScript blog, we’ll cover the following basic fundamentals of JavaScript..
How Major Companies Are Using JavaScript
Microsoft
Okay, so you’re probably not going to find JavaScript powering Windows anytime soon, but Microsoft relies on JavaScript for a whole lot else.
First off, Microsoft needs to work closely with JavaScript to built its Edge web browser. All browsers need to process and execute JavaScript efficiently, so Microsoft has developed and maintains its own JavaScript engine for Edge.
Recently, Microsoft has really embraced NodeJS. They thoroughly support Node on the Azure cloud platform. Its one of Azure’s major features, and they’ve integrated Visual Studio support for Node.
PayPal
PayPal has obviously been using JavaScript on the front end of their website for a long time, but that’s only the beginning.
The online payment giant was one of the earliest adopters of NodeJS. During an overhaul of their account overview page, they decided to try building the page in Node at the same time as their usual Java development. The NodeJS version worked out so well, that they chose to use it in production and build all client-facing applications in Node going forward.
Netflix
Like PayPal, Netflix started out using Java for just about everything. They too ran into problems with Java’s size and the time it required to develop.
Over time, Netflix moved away from its more traditional structure into the cloud and started to introduce NodeJS. With Node, Netflix was able to break down pieces of their user interface into individual services. This more distributed approach was able to speed things up an alleviate stress on their servers. Today, a large portion of Netflix’s interface is running on Node.
Groupon
Groupon used to be infamously slow. Why? They were powered by Ruby on Rails. That’s the same framework that brought you the Twitter fail whale.
Groupon was all one gigantic Ruby on Rails application. Thanks to difficulties in speed and maintainability, they decided to change over to NodeJS. Node allowed Groupon to rebuild their entire US website by breaking down everything into individual NodeJS web applications. Now, Groupon is made up of over 20 Node applications, and it moves much faster as a whole.
Uber
Uber needs to handle loads of data in real time. They have millions of requests coming in continuously, and that’s not just hits on a page. Uber needs to track driver locations, rider locations, and incoming ride requests. It has to seamlessly sort that data and match riders as fast as possible.
All of that plays to NodeJS’s and JavaScript’s strengths. Node is designed to handle requests and hand off data quickly. It’s asynchronous capabilities are a huge part of that. Node is central to Uber’s user facing stack for just that reason.
You’re probably aware that Facebook uses JavaScript. It’s kind of hard to miss. What’s probably not as obvious is exactly how much JavaScript goes into making Facebook and how much Facebook is involved in JavaScript development.
You may have noticed the way that Facebook loads. Each piece of the page is separate. Facebook has invented its own way of breaking down and delivering sections of JavaScript separately.
It doesn’t stop there. Facebook created React, one of the most popular front end frameworks. Facebook uses React on Facebook.com as well as Instagram and WhatsApp.
How doesn’t Google use JavaScript? Seriously, it’s everywhere. Google’s search results that spring up as your typing get there with JavaScript. The Gmail web client is powered by JavaScript. Google Docs? Yeah, that’s JavaScript too.
Google develops and usually open sources it’s own JavaScript tools. The most obvious example is AngularJS. Angular is used most prominently in Google’s DoubleClick advertising platform, but it’s also one of the most popular front end frameworks available. It’s even part of the MEAN stack.
Google developed Chrome. Chrome, being a web browser, needed a JavaScript engine, so Google also made V8. V8 not only powers Chrome, it’s at the heart of NodeJS. So, without Google, there would be no Node.
eBay
eBay’s story is a lot like Netflix’s. For a long time, just about everything in eBay’s tech stack was based on Java. A few years ago, eBay encountered a problem that Java wasn’t the right solution for. They decided to give NodeJS a shot instead.
Node worked so well that eBay not only kept using it for that particular service, they began migrating their entire user facing stack to NodeJS. Now, just about everything that you interact with on eBay is powered by Node. Sure, beneath Node, Java is still dealing with their databases, but eBay still places a lot of trust in NodeJS.
Walmart
Most people probably don’t think of Walmart as a tech company, but because they’re one of the largest retailers in the world, their online retail business is gigantic. It’s not much of a stretch to see how they need build a technologically advanced web application do drive their online business.
Walmart started out with Java. It’s a solid enterprise-grade platform that has been the de facto choice for years. However, Walmart needed something faster and lighter weight for their mobile site. So, they turned to NodeJS.
Once again, Walmart began to see Node as a valid Java replacement in loads of other places. Today, the Walmart.com that you see is powered by Node.
LinkedIn relies on NodeJS for its mobile site. A few years back, LinkedIn used Rails for its mobile site. As with other other large Rails applications, it was slow, monolithic, and it scaled poorly.
LinkedIn switched over to NodeJS to solve its scaling problems. Node’s asynchronous capabilities allowed the LinkedIn mobile site to perform more quickly than before while using fewer resources. Node also made data sharing and building APIs easier for the LinkedIn developers.
And Lot’s More….
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