Top 29 Html 5 Interview Questions You Must Prepare 21.Apr.2024

HTML 5 comes with a standard way of embedding audio files as previously we don’t have any such support on a web page. Supported audio formats are as follows:
•MP3
•Wav
•Ogg.

Below is the most simple way to embed an audio file on a web page.
<audio controls>
    <source src=”jamshed.mp3″ type=”audio/mpeg”>
    Your browser does’nt support audio embedding feature.
</audio>

In above code, src value can be relative as well as absolute URL. We can also use multiple <source> elements pointing to different audio files. There are more new attributes for <audio> tag other than src as below:
•controls – it adds controls such as volume, play and pause.
•autoplay – it’s a boolean value which specifies that audio will start playing once it’s ready.
•loop – it’s also a boolean value which specifies looping (me it automatically start playing after it ends).
•preload – auto, metadata and none are the possible values for this attribute.
     •auto me plays as it loaded.
     •metadata displays audio file’s associated data
     •none me not pre-loaded.

The sessionStorage object stores the data for one session. The data is deleted when the user closes the browser window. like below we can create and access a sessionStorage here we created "name" as session:

  <script type="text/javascript">
sessionStorage.name="PCDS";
document.write(sessionStorage.name);
</script>

HTML 5 comes up with many new features including video/audio elements for media playback and better support for local offline storage.

One of the key feature of HTML 5 is “Application Cache” that enables us to make an offline version of a web application. It allows to fetch few or all of website contents such as HTML files, CSS, images, javascript etc locally. This feature speeds up the site performance. This is achieved with the help of a manifest file defined as follows:
<!doctype html>
.....

As compared with traditional browser caching, Its not compulsory for the user to visit website contents to be cached.

In order to achieve Application Cache feature in HTML5, a manifest file is used as follows: 
<!doctype html>
…..

Manifest file is basically a text file that dictates what needs to be cache or not if Application Cache is enabled. Followings are the four main sections of a manifest file where CACHE MANIFEST is the only required section: 

•CACHE MANIFEST
•CACHE
•NETWORK
•FALLBACK

It is a rectangular area, where we can control every pixel.

HTML 5 has the capability to store data locally. Previously it was done with the help of cookies. Exciting thing about this storage is that its fast as well as secure.

There are two different objects which can be used to store data.
•localStorage object stores data for a longer period of time even if the browser is closed.
•sessionStorage object stores data for a specific session.

HTML5 is nothing more then upgreaded version of HTML where in HTML5 Lot of new future like Video, Audio/mp3, date select function , placeholder , Canvas, 2D/3D Graphics, Local SQL Database added so that no need to do external plugin like Flash player or other library.

Before HTML5 LocalStores was done with cookies. Cookies are not very good for large amounts of data, because they are passed on by every request to the server, so it was very slow and in-effective. 

In HTML5, the data is NOT passed on by every server request, but used ONLY when asked for. It is possible to store large amounts of data without affecting the website's performance and the data is stored in different areas for different websites, and a website can only access data stored by itself.

And for creating localstores just need to call localStorage object like below we are storing name and address

  <script type="text/javascript">
localStorage.name="PCDS";
document.write(localStorage.name);
</script> 
<script type="text/javascript">
localStorage.address="Mumbai India..";
document.write(localStorage.address);
</script>

It is used for heading sections. Header tags used are from <h1> to <h6>. The largest is the main heading of the section, and the others are sub-headings.

<video src="movie.ogg" controls="controls"></video>

Normally if some script is executing in an HTML page, the page remains unresponsive until the scripts execution stops. But an HTML5 web worker is a script (i.e. JavaScript) that keeps executing in background. At the same time user can interact with the page and will not feel any performance degradation.HTML5 Web Worker

HTML5 web worker normally exists in external files and used for long-running CPU intensive tasks but without affecting the User Interface or other scripts.

Below are the New Markup Elements added in HTML5

Below are the New Media Elements have added in HTML5

yes we can use Canvas element in html5 like below
<canvas>.

The canvas element is used to draw graphics images on a web page by using javascript like below

  <canvas id="pcdsCanvas" width="500" height="400"></canvas>   <script type="text/javascript">
var pcdsCanvas=document.getElementById("pcdsCanvas");
var pcdsText=pcdsCanvas.getContext("2d");
pcdsText.fillStyle="#82345c";
pcdsText.fillRect(0,0,150,75);
</script>

<canvas id="myCanvas" width="200" height="100"></canvas>

HTML 5 has strong support for media. Other than audio and video tags, it comes with the following tags:

<embed> Tag: <embed> acts as a container for external application or some interactive content such as a plug-in. Special about <embed> is that it doesn’t have a closing tag as we can see below:

<embed type=”video/quicktime” src=”Fishing.mov”>

<source> Tag: <source> is helpful for multiple media sources for audio and video.

<video width=”450″ height=”340″ controls>
     <source src=”jamshed.mp4″ type=”video/mp4″>
     <source src=”jamshed.ogg” type=”video/ogg”>
</video>

<track> Tag: <track> defines text track for media like subtitles as:

<video width=”450″ height=”340″ controls>
     <source src=”jamshed.mp4″ type=”video/mp4″>
     <source src=”jamshed.ogg” type=”video/ogg”>
     <track kind=”subtitles” label=”English” src=”jamshed_en.vtt” srclang=”en” default></track>
      <track kind=”subtitles” label=”Arabic” src=”jamshed_ar.vtt” srclang=”ar”></track>
</video>

HTML 5 standard comes with a number of new APIs. Few of it are as follows:

•Media API
•Text Track API
•Application Cache API
•User Interaction
•Data Trfer API
•Command API
•Constraint Validation API
•History API
•and many more

Elements that are deprecated from HTML 4 to HTML 5 are:
•frame
•frameset
•noframe
•applet
•big
•center
•basefront

Yes we can use below new input type Attribute in HTML5

Type	                    Value  tel	        The input is of type telephone number  search	        The input field is a search field  url	        a URL  email	        One or more email addresses  datetime	A date and/or time  date	        A date  month	        A month  week	        A week  time	        The input value is of type time  datetime-local	A local date/time  number	        A number  range	        A number in a given range  color	        A hexadecimal color, like #82345c  placeholder	Specifies a short hint that describes the expected value                   of an input field  

HTML5 Web worker seems to be very handy in many scenarios (especially for CPU intensive tasks) but it has certain limitations. Few JavaScript objects are not accessible to HTML5 web worker as:
•parent object
•window object
•document object

The <!DOCTYPE> is an instruction to the web browser about what version of HTML the page is written in. AND The <!DOCTYPE> tag does not have an end tag and It is not case sensitive.

The <!DOCTYPE> declaration must be the very first thing in HTML5 document, before the <html> tag. As In HTML 4.01, all <! DOCTYPE > declarations require a reference to a Document Type Definition (DTD), because HTML 4.01 was based on Standard Generalized Markup Language (SGML). WHERE AS HTML5 is not based on SGML, and therefore does not require a reference to a Document Type Definition (DTD).

Forms Section in HTML5 is known as Web Forms 2.@It’s basically an extension to HTML4 forms features. Web Forms 2.0 in HTML5 provides comparatively a greater degree of semantic markups than HTML4 as well as removing the need of lengthy and tedious scripting and styling, as a result making HTML5 more richer but simpler in use.

Cache manifest file is simply a text file that dictates the browser, what to store for offline access? It basically list down the required resources for offline access.

</> Following is an example of a simple manifest file:

CACHE MANIFEST
/decorate.css
/work.js
/amazing.jpg

So, the resources mentioned in above manifest file (decorate.css, work.js, and amazing.jpg) will be downloaded and cached locally for offline access.

HTML or Hypertext Markup Language is a formatting language that programmers and developers use to create documents on the Web. The latest edition HTML5 has enhanced features for programmers such as <video>, <audio> and <canvas> elements. You view a Web page written in HTML in a Web browser such as Internet Explorer, Mozilla Firefox or Google Chrome. The HTML5 language has specific rules that allow placement and format of text, graphics, video and audio on a Web page. Programmers use these programming tags or elements to produce web pages in unique and creative ways. Tags such as <section>, <article>, <header> enable the creator to make a more efficient and intelligent web page. Users will not have to use a Flash plug-in for video and audio content. Visual Studio users typically write code in HTML5 when creating web site content.

Like below we can add video in html5

     <video  width="320" height="240" controls="controls">
  <source src="pcds.mp4" type="video/mp4" />
  <source src="pcds.ogg" type="video/ogg" />
  </video>

And audio like this 

    <audio controls="controls">
  <source src="song.ogg" type="audio/ogg" />
  <source src="song.mp3" type="audio/mpeg" />
  </audio>