FRONT-END TECHNOLOGIES

Developing Simple and Intuitive UI that Improves the Way our Clients Work

Maximize user experience through responsive, user-friendly and interactive designs.

Every business firm wants to have a feature-rich, functional, and user-friendly website or App to attract and retain customers in today’s competitive environment.This is where quality front-end web development plays a decisive role in making a business website appealing with impeccable performance.



With AngularJS, you can never go wrong.


To come-up with top notch apps, you could contract an AngularJS development company or hire AngularJS developer. Picking the right AngularJS development services provider will help you to get customized apps and guarantee for faster business progress.Codezilla is one stop destination for all your needs.Two way data binding, power of MVVM , Easy testing, Requires less code writing, this features make app development easy and result very intuitive.



AngularJS is an open-source JavaScript framework designed for creating dynamic single web page applications with fewer lines of code.

Some of the key advantages of using AngularJS framework include:
It provides an excellent “desktop-like” experience to the end-user.
By freeing the developer from having to register callbacks manually or write repetitive low-level DOM manipulation tasks, it saves months of development.
By separating DOM manipulation from app logic, it makes code modular and easy to test.
It supports two-way data binding.

To adapt to the new AngularJS 1.5 components, you would need to change .directive to component.

  • Scope
  • Controller
  • Model
  • View
  • Services
  • Data Binding
  • Directives
  • Filters
  • Testable

The scope is a unique JavaScript object that plays the role of joining the controller (JavaScript) with the views (HTML). The controller sets properties on the scope, and the view binds to them.

Each AngularJS application has only one root scope. Child controllers, however, create scope for each view. When the new scopes are created, they are added to their parent root scope as child scopes. This creates a hierarchical structure when they are attached.

Data binding is the automatic attunement of data between the view and model components. AngularJS uses two-way data binding. In one-way binding, the scope variable in the HTML is set to the first value that its model is assigned to.
In two-way binding, the scope variable changes its value every time its model binds to a different value.

Directives are unique markers on a DOM element that tell the HTML compiler to attach a specified behavior to the DOM element. Directives start with ng-prefix. Some of the built-in directives include ngClass, ngApp, ngRepeat, ngModel, ngBind and ngInit. List the different types of directives.

    There are four types of directives:
  • Comment directives
  • CSS class directives
  • Attribute directives
  • Element directives

You can use a directive as an element, attribute, or class name. To define the way your directive will be used, you need to set the restrict option in the directive declaration. The restrict option can be set to:

  • ‘A’ - Only matches attribute name
  • ‘C’ - Only matches class name
  • ‘E’ – Only matches element name

You can combine these restrictions to produce needed results.

During every digest cycle, all new scope model values are compared against the previous values. This is called dirty checking. If change is detected, watches set on the new model are fired, and another digest cycle executes. This goes on until all models are stable.
The digest cycle is triggered automatically, but it can be called manually using “.$apply().”

    The common ways of communication include:
  • Using Event
  • Using services
  • By assigning models on $rootScope
  • Directly between controllers using ControllerAs and other forms of inheritance
  • Directly between controllers using $parent, $$childHead, $$nextSibling

The link function combines the directives with a scope to produce a live view. The link function is responsible for instance DOM manipulation and for registering DOM listeners. The compile function is responsible for template DOM manipulation as well as the collection of all the directives.

End-to-end (e2e) testing involves testing an application from start to finish to determine whether all the components are working correctly. It catches issues within an application related to integration and flow.

Dependency injection is the process where the dependent objects are injected rather than being created by the consumer.

Dependency injection has two significant benefits: Testing and decoupling.

SPA is the concept whereby pages are loaded from the server not by doing postbacks, instead of by creating a single shell page or master page and loading the web pages into the master page.

SPA can be implemented with Angular by using Angular routes.

    Use one-time Angular binding
  • Use web worker
  • Work in batches
  • Cache DOM
  • Remove unnecessary watchers
  • Use one-time Angular binding

React JS is doubtless non-risky, advanced and responsive.


Aiming primarily to provide speed, simplicity, and scalability, React.js helps build and support highly dynamic web and mobile applications. It facilitates the developers’ work and the users’ interaction with the product. Reusable and highly testable React.js components further increase development speed and quality.the giants like Facebook, Airbnb, DropBox, IMDb, Instagram, Netflix, PayPal, Tesla Motors, and Walmart are using React.js framework due to its great efficiency.



React is a front-end JavaScript library developed by Facebook in 2011. It follows the component based approach which helps in building reusable UI components. It is used for developing complex and interactive web and mobile UI. Even though it was open-sourced only in 2015, it has one of the largest communities supporting it.

Major features of React are listed below: It uses the virtual DOM instead of the real DOM.
It uses server-side rendering.
It follows uni-directional data flow or data binding.

Some of the major advantages of React are - It increases the application’s performance. It can be conveniently used on the client as well as server side, Because of JSX, code’s readability increases React is easy to integrate with other frameworks like Meteor, Angular, etc Using React, writing UI test cases become extremely easy.

Limitations of React are listed below:
React is just a library, not a full-blown framework, Its library is very large and takes time to understand. It can be little difficult for the novice programmers to understand Coding gets complex as it uses inline templating and JSX

A virtual DOM is a lightweight JavaScript object which originally is just the copy of the real DOM. It is a node tree that lists the elements, their attributes and content as Objects and their properties. React’s render function creates a node tree out of the React components. It then updates this tree in response to the mutations in the data model which is caused by various actions done by the user or by the system.

Browsers can only read JavaScript objects but JSX in not a regular JavaScript object. Thus to enable a browser to read JSX, first, we need to transform JSX file into a JavaScript object using JSX transformers like Babel and then pass it to the browser.

Components are the building blocks of a React application’s UI. These components split up the entire UI into small independent and reusable pieces. Then it renders each of these components independent of each other without affecting the rest of the UI.

Each React component must have a render() mandatorily. It returns a single React element which is the representation of the native DOM component. If more than one HTML element needs to be rendered, then they must be grouped together inside one enclosing tag such as "form", "group","div" etc. This function must be kept pure i.e., it must return the same result each time it is invoked.

States are the heart of React components. States are the source of data and must be kept as simple as possible. Basically, states are the objects which determine components rendering and behavior. They are mutable unlike the props and create dynamic and interactive components. They are accessed via this.state().

Arrow functions are more of brief syntax for writing the function expression. They are also called ‘fat arrow‘ (=>) the functions. These functions allow to bind the context of the components properly since in ES6 auto binding is not available by default. Arrow functions are mostly useful while working with the higher order functions.


A reliable and progressive framework.


Vue.js is an open-source JavaScript framework that can develop single page web applications. It can streamline web development by using as a web application framework. Vue is smaller, faster and flexible. It provides ease in development due to rich HTML templates. The documentation is up-to-date, and the syntax is simple.Vue.js will serve you in better form if you want to integrate a front-end JavaScript framework into an existing application
Companies familiar with Vue.js are Behance, Xiaomi, Laracasts, Codeship, Gitlab, Alibaba, Facebook, Netflix, Grammarly and Adobe.



Vue.js is able to deliver the plain JavaScript object syntax without resorting to dirty checking by using Object.defineProperty, which is an ECMAScript 5 feature. It only works on DOM elements in IE8 and there’s no way to polyfill it for JavaScript objects.

Yes and No. Vue.js only converts normal properties into getters and setters so it can get notified when the properties are accessed or changed. When serialized, your data will look exactly the same. There are, of course, some caveats:
When you console.log observed objects you will only see a bunch of getter/setters. However you can use vm.$log() to log a more inspectable output.
You cannot define your own getter/setters on data objects. This isn’t much of a problem because data objects are expected to be obtained from plain JSON and Vue.js provides computed properties.
Vue.js adds a few extra properties/methods to observed objects: __ob__, $add, $set and $delete. These properties are innumerable so they will not show up in for ... in ... loops. However if you overwrite them things will likely break.
That’s pretty much it. Accessing properties on the object is the same as before, JSON.stringify and for ... in ... loops will work as normal. 99.9% of the time you don’t even need to think about it.

Vue.js has gone through some API changes in the latest 0.12 release, but this is the last planned point release before 1.0. In the meanwhile, there already companies/projects using Vue.js in production.

Vue.js is free and fully open sourced under the MIT License.

There are a few reasons to use Vue over Angular, although they might not apply for everyone:
Vue.js is a more flexible, less opinionated solution. That allows you to structure your app the way you want it to be, instead of being forced to do everything the Angular way. It’s only an interface layer so you can use it as a light feature in pages instead of a full blown SPA. It gives you bigger room to mix and match with other libraries, but you are also responsible for making more architectural decisions. For example, Vue.js’ core doesn’t come with routing or ajax functionalities by default, and usually assumes you are building the application using an external module bundler. This is probably the most important distinction.
Vue.js is much simpler than Angular, both in terms of API and design. You can learn almost everything about it really fast and get productive.
Vue.js has better performance and is much, much easier to optimize, because it doesn’t use dirty checking. Angular gets slow when there are a lot of watchers, because every time anything in the scope changes, all these watchers need to be re-evaluated again. Also, the digest cycle may have to run multiple times to “stabilize” if some watcher triggers another update. Angular users often have to resort to esoteric techniques to get around the digest cycle, and in some situations there’s simply no way to optimize a scope with a large amount of watchers. Vue.js doesn’t suffer from this at all because it uses a transparent dependency-tracking observing system with async queueing - all changes trigger independently unless they have explicit dependency relationships. The only optimization hint you’ll ever need is the track-by param on v-repeat lists.
Vue.js has a clearer separation between directives and components. Directives are meant to encapsulate DOM manipulations only, while Components stand for a self-contained unit that has its own view and data logic. In Angular there’s a lot of confusion between the two. But also note that Vue.js is a relatively young project, while Angular is battle-proven, Google-sponsored, and has a larger community.

React and Vue.js do have some similarity in that they both provide reactive & composable View components. However the internal implementation is fundamentally different. React is built upon a virtual DOM - an in-memory representation of what the actual DOM should look like. Data in React is largely immutable and DOM manipulations are calculated via diffing. On the contrary data in Vue.js is mutable and stateful by default, and changes are triggered through events. Instead of a virtual DOM, Vue.js uses the actual DOM as the template and keeps references to actual nodes for data bindings.
The virtual-DOM approach provides a functional way to describe your view at any point of time, which is really nice. Because it doesn’t use observables and re-renders the entire app on every update, the view is by definition guaranteed to be in sync with the data. It also opens up possiblities to isomorphic JavaScript applications.
Overall I’m a big fan of React’s design philosophy myself. But one issue with React (or JSX) is that your render function often involves a lot of logic, and ends up looking more like a piece of program (which in fact it is) rather than a visual representation of the interface. For some developers this is a bonus, but for designer/developer hybrids like me, having a template makes it much easier to think visually about the design and CSS. JSX mixed with JavaScript logic breaks that visual model I need to map the code to the design. In contrast, Vue.js pays the cost of a lightweight DSL (directives) so that we have a visually scannable template and with logic encapsulated into directives and filters.
Another issue with React is that because DOM updates are completely delegated to the Virtual DOM, it’s a bit tricky when you actually want to control the DOM yourself (although theoretically you can, you’d be essentially working against the library when you do that). For applications that needs ad-hoc custom DOM manipulations, this can become a pretty annoying restriction. On this front, Vue.js allows for more flexibility and there are multiple FWA/Awwwards winning sites built with Vue.js.

Polymer is yet another Google-sponsored project and in fact was a source of inspiration for Vue.js as well. Vue.js’ components can be loosely compared to Polymer’s custom elements, and both provide a very similar development style. The biggest difference is that Polymer is built upon the latest Web Components features, and requires non-trivial polyfills to work (with degraded performance) in browsers that don’t support those features natively. In contrast, Vue.js works without any dependencies down to IE9.
Also, in Polymer 1.0 the team has really made its data-binding system very limited in order to compensate for the performance. For example, the only expressions supported in Polymer templates are the boolean negation and single method calls. Its computed property implementation is also not very flexible.
Finally, when deploying to production, Polymer elements need to be bundled via a Polymer-specific tool called vulcanizer. In comparison, single file Vue components can leverage everything the Webpack ecosystem has to offer, and thus you can easily use ES6 and any CSS pre-processors you want in your Vue components.

First, Vue provides a cleaner syntax in getting and setting VM properties.
On a higher level, Vue differs from Knockout in that Vue’s component system encourages you to take a top-down, structure first, declarative design strategy, instead of imperatively build up ViewModels from bottom up. In Vue the source data are plain, logic-less objects (ones that you can directly JSON.stringify and throw into a post request), and the ViewModel simply proxies access to that data on itself. A Vue VM instance always connects raw data to a corresponding DOM element. In Knockout, the ViewModel essentially is the data and the line between Model and ViewModel is pretty blurry. This lack of differentiation in Knockout makes it much more likely to result in convoluted ViewModels.

Riot 2.0 provides a similar component-based development model (which is called a “tag” in Riot), with a minimal and beautifully designed API. I think Riot and Vue share a lot in design philosophies. However, despite being a bit heavier than Riot,

    Vue does offer some significant advantages over Riot:
  • True conditional rendering (Riot renders all if branches and simply show/hide them)
  • A far-more powerful router (Riot’s routing API is just way too minimal)
  • More mature tooling support (see webpack + vue-loader)
  • Transition effect system (Riot has none)
  • Better maintenance status (As of Aug 31st 2015, Riot has 25 open bugs while Vue has zero)
  • Better performance. (Riot in fact uses dirty checking rather than a virtual-dom, and thus suffers from the same perf issues with Angular.)


JavaScript is everywhere and universal.


The benefits of choosing JavaScript for are: Modern, enhanced UI without costing much Powerful security aspects due to its wider usage in front-end as well as in back-end programming Constantly evolving due to the open-source community Fewer dependencies, flexibility, and incredibly-faster performance Runs on the majority of the platforms(app, web, mobile web, PWA, and desktop) Apart From The Mobile, Web, And Desktops, JavaScript Can Accomplish The Following Types Of Applications:
Chatbots and AI
Gaming applications
Machine Learning
IoT and Robots



JavaScript is prototype-based scripting language.

Netscape Communications Corporation, Mozilla Foundation.

Single line comment followed by '//' and Block of comments placed between '/*' and '*/'.

Alert, Confirm and Prompt.

Document Object Model (DOM) is an application programming interface (API).

DOM is used to access logical structure of the HTML document.

Using DOM we can access, modify, change CSS styles, create Elements and Text nodes, delete Elements.

We can access Element in the document.

Using 'innerHTML' property we can change the content of Element. Example:
document.getElementById("element_id_name").innerHTML = "New text";

By adding attribute to 'document.getElementById()'. Example:
document.getElementById("element_id_name").align = "center";

By adding style.propertyname to 'document.getElementById()'. Example:
document.getElementById("element_id_name").style.backgroundColor = "orange";

  • onClick
  • onChange
  • onFocus
  • onBlur
  • onSubmit
  • onLoad
  • onMouseOver
  • onMouseOut

By using 'document.createElement()'.

By using 'document.createTextNode()'.

By using 'appendChild()'.

By using 'removeChild()'.

In Document Object Model, every element is called as Node.

  • Number
  • String
  • Math
  • Date
  • Array
  • window
  • document
  • location
  • history
  • screen

By using 'window.innerWidth' and 'window.innerHeight'.

By using 'history.back()'.

By using 'history.forward()'.

By using 'location.href'.