Front end Developer Interview Questions

Front end Developer Interview Questions
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Below are the list of Best Front end Developer Interview Questions and Answers

HTML (HyperText Markup Language) is a markup language to design the web page. It is used to display the contents of the web page in order. They are the building blocks of the HTML pages. This text-based markup language creates documents by denoting structural semantics.

The HTML elements such as headings, paragraphs, lists, links, quotes, and other items are delineated by tags. HTML was developed by WHATWG and first released in 1993.

Ajax (Asynchronous Javascript and XML) is a technique to create asynchronous web applications. Applications developed with Ajax can send and retrieve data asynchronously from the server without interfering with the existing page of the application. It sends and receives data in the background.

Ajax is not a single technology but a combination of technologies such as HTMML, CSS, DOM, JSON, XML, XMLHttpRequest, and JavaScript.

NPM stands for Node Package Manager. It is used to install, uninstall, update packages for Javascript Programming Language. NPM also is a default package manager for Node.js.

REST stands for Representational State Transfer. It is an architectural style that defines a set of standards to create web services or API.

JSON-P (JSON with padding) is a technique of Javascript which allows you to return back to the JSON data from a remote server. When we create a script node dynamically with a cross-domain source then in case of returning Javascript function to a remote site there is a need for evaluation of that function. In the case of JSON, you can only get particular data from a remote server but in case you want to stick to the returned data then there is a need to use a Javascript function which is JSONP. It becomes easy to use JSONP with jQuery.

CSS sprites are a combination of multiple images into a single file that we use on our website. CSS sprites help us to load our page faster by reducing the number of file requests.

To clear float property is used to clear the float property after it is used on an element. You should match the cleat to the float when clearing it.

Mixins in CSS is used to define patterns of property-value pairs that can be reused. It is used by the document authors to group vendor prefixes and to simplify the code.

To define a mixin, the @mixin keyword should be followed by the mixin name with a declaration block.

//example of mixin definition
@mixin .rounded7px {
  -moz-border-radius: 7px;

The Grid layout in the CSS offers a grid-based system with rows and columns to place the HTML elements. It removes the need for using floats and positioning. It consists of one parent element and one or more child elements placed in rows and columns. This design system is supported in all modern browsers.

//example of the grid design system in CSS
<div class="grid-container">
  <div class="grid-item">1
  <div class="grid-item">2
  <div class="grid-item">3

There are three ways to include a CSS file in the web page. They are,

External CSS

Here, an external CSS file is linked to an HTML page to apply the changes created in that file.

//example of linking external CSS file
<link rel="stylesheet" type="text/css" href="mystyle.css">

Internal CSS

Here, a separate CSS block is inserted into the HTML page. This CSS code is defined within the </style> tag.

//example of </style> tag definition
body {
  background-color: black;

Inline CSS

Here, each CSS style is embedded in the HTML tags to apply style for than a single element.

//example of Inline CSS
<p style="color:red;">This is a paragraph.</p>