Web Development Interview Questions

W3C stands for World Wide Web Consortium which is the international standard for World Wide Web. W3C is constantly busy trying to standardize the web and to make it accessible to all users. The company was created in 1994.
There is not a big difference between the two. HTML5 is a continuum of HTML. There has been no major paradigm shift. From a broader viewpoint, HTML was a simple language for laying out text and images on a webpage, whereas HTML5 can be viewed as a development platform that does what HTML does that and more, including better support for audio, video, and interactive graphics. It has a number of new elements, supports offline data storage for applications, and has more robust exchange protocols.
Among others: Media API, Text Track API, Application Cache API, User Interaction, Data Transfer API, Command API, and the History API.
The z-index property specifies the stack order of an element within the document area (or a part of it). An element with greater stack order will always be in front of an element with a lower stack order. However, z-index only works on positioned elements (position:absolute, position:relative, or position:fixed). It can have four kind of values:
Auto: Sets the stack order equal to its parents.
Number: Orders the stack order.
Initial: Sets this property to its default value (0).
Inherit: Inherits this property from its parent element.
Well, jQuery is not a programming language, but a well written JavaScript code (a framework). It is a library built with Javascript. Javascript is the core programming language. It is very popular because it abstracts away cross-browser compatibility issues and emphasises unobtrusive and callback-driven Javascript programming.
Events are actions performed on specific conditions.. When we perform these actions on an HTML page, we can do whatever we want. We then use event handlers to perform the action. Some important handlers are for example: bind(), unbind(), blur(), off(), hover(), on(), one(), ready(),trigger() etc.
In short, preventDefault(): Stops the default action of an element from happening. event.stopPropagation(): Prevents the event from bubbling up the DOM tree, thus preventing any parent handlers from being notified of the event.
AJAX stands for “Asynchronous JavaScript and XML”. AJAX is about exchanging data with a server, without reloading the whole page. It is a technique for creating fast and dynamic web pages.
$.ajax() – Performs an async AJAX request.
$.get() – Loads data from a server using an AJAX HTTP GET request.
$.post() – Loads data from a server using an AJAX HTTP POST request.
An AJAX request can be in any of the following formats:
Text File
JSON Object
You can do following things to reduce the page load time
Reduce image size
Remove unnecessary widgets
HTTP compression
Placing CSS at the top and script reference at the bottom or in external files
Reduce lookups
Minimize redirects
- Javascript uses the XMLHttpRequest object to manipulate XML and other text data between client and server.
- AJAX applications use the XMLHttpRequest object to avoid the postback of entire page when the browser is communicating with server.
- The XMLHttpRequest object enables a client-side script to execute an HTTP request.
- For this functionality MSXML ActiveX component is used in earlier version of Internet Explorer. While, XMLHttpRequest is used in Internet Explorer 7 and other browsers, such as Mozilla, Firefox.
- The AccordionExtender control is almost same as the CollapsiblePanelExtender control.
- It enables the grouping of multiple collapsible panels in a single control.
- It also manages the collapsed and expanded state of every panel and one panel will expand at a time.
- Using AccordionExtender control we can’t expand two or more panels at a time.
JSON syntax is a set of the JavaScript object notation syntax.
Data is in name/value pairs
Data is separated by comma
Curly brackets hold objects
Square bracket holds arrays
To convert a string into a JSON array, you need to create a JSONObject object for each of your objects, and add those to your JSON array.
MIME type for JSON text is “application/json”
The key components of Bootstrap are
CSS : It comes with plenty of CSS files
Scaffolding : It provides a basic structure with Grid system , link styles and background
Layout Components : List of layout components
JavaScript Plugins: It contains many jQuery and JavaScript plugins
Customize: To get your own version of framework you can customize your components
lass loader is a part of JRE (Java Runtime Environment) which loads Java classes into Java virtual environment. Class loaders also does the process of converting a named class into its equivalent binary form. 5
JSON: JSON is a simple data format used for communication medium between different systems
JSONP: It is a methodology for using that format with cross domain ajax requests while not being affected by same origin policy issue.
In Bootstrap there are two types of Layout available
Fluid Layout: Fluid layout is used when you want to create a app that is 100% wide and use up all the width of the screen
Fixed Layout: For a standard screen you will use fixed layout (940 px) option
A content delivery network or content distribution network (CDN) is a large distributed system of servers deployed in multiple data centers across the Internet. The goal of a CDN is to serve content to end-users with high availability and high performance.
To work with an element on the web page, first we need to find them. To find the html element in jQuery we use selectors. There are many types of selectors but basic selectors are:
Name: Selects all elements which match with the given element Name.
#ID: Selects a single element which matches with the given ID
.Class: Selects all elements which match with the given Class.
Universal (*): Selects all elements available in a DOM.
Multiple Elements E, F, G: Selects the combined results of all the specified selectors E, F or G.
Attribute Selector: Select elements based on its attribute value.
The .animate() method allows us to create animation effects on any numeric CSS property. This method changes an element from one state to another with CSS styles. The CSS property value is changed gradually, to create an animated effect.
Pagination is the handling of an unordered list by bootstrap. To handle pagination bootstrap provides following classes
.pagination: To get pagination on your page you have to add this class
.disabled, .active: Customize links by .disabled for unclickable links and .active to indicate the current page
.pagination-Ig, .pagination-sm: Use these classes to get different size item
In bootstrap, Jumbotron is generally used for content that you want to highlight like some slogan or marketing headline etc. in other words it is used to enlarge the size of the headings and to add a margin for landing page content
To use the Jumbotron in Bootstrap
Create a container div with the class of .jumbotron
The Carousel plugin is used to add a slider to your site. It is useful in condition where you want to display huge amount of contents within a small space on the web pages. Some of the standard carousel includes
.carousel (options) .carousel (cycle) .carousel (pause) .carousel (number) .carousel (prev) .carousel (next)
There are quite a lot of ways you can reduce load time:
Enable browser caching
Optimize images
Minify resources
Minimize HTTP Requests
Reduce redirects

An image map is a list of coordinates relating to a specific image, created in order to hyperlink areas of the image to different destinations (as opposed to a normal image link, in which the entire area of the image links to a single destination).
CSS can be applied in the following three ways:
Linked: Create a separate .css file and add all the style for the web page there. Make sure the file is linked to the HTML document(s) using the link tag
Embedded: Inside the HTML document, open a style tag and inside that, add all styles just like you’d do on a linked file.
Inline: This is done by adding a style attribute inside an HTML element.
The following is a list of new properties added in CSS3:
Also, other features like multiple backrounds which allows you to have two or more background in the very same selector and flexible box model which ensures that elements behave predictably when the page layout must accommodate different screen sizes and different display devices.
An anonymous function can be defined in similar way as a normal function but it would not have any name.
The not(selector) method removes elements matching the specified selector from the set of matched elements.
The preventDefault() method of Event object prevents the browser from executing the default action.?
The isPropagationStopped() method of Event object returns whether event.stopPropagation() was ever called on this event object.
The ready(fn) function binds a function to be executed whenever the DOM is ready to be traversed and manipulated.
The ready(fn) function binds a function to be executed whenever the DOM is ready to be traversed and manipulated.
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