Friday, 20 January 2017

Top 25 Recent Best HTML5 and CSS3 Interview Questions & Answers




* What is SVG and advantages of SVG?
SVG is a language for describing two-dimensional vector graphics in XML.
SVG stands for Scalable Vector Graphics
SVG is used to define vector-based graphics for the Web
SVG defines the graphics in XML format
SVG graphics do NOT lose any quality if they are zoomed or resized
Every element and every attribute in SVG files can be animated
Advantages:
Advantages of using SVG over other image formats (like JPEG and GIF) are:
SVG images can be created and edited with any text editor
SVG images can be searched, indexed, scripted, and compressed
SVG images are scalable
SVG images can be printed with high quality at any resolution
SVG images are zoomable (and the image can be zoomed without degradation)
Differences Between SVG and Canvas:
SVG is a language for describing 2D graphics in XML.
Canvas draws 2D graphics, on the fly (with a JavaScript).
SVG is XML based, which means that every element is available within the SVG DOM. You can attach JavaScript event handlers for an element.
In SVG, each drawn shape is remembered as an object. If attributes of an SVG object are changed, the browser can automatically re-render the shape.
Canvas is rendered pixel by pixel. In canvas, once the graphic is drawn, it is forgotten by the browser. If its position should be changed, the entire scene needs to be redrawn, including any objects that might have been covered by the graphic.
Difference between Transitional and Strict doctype.
Strict : This DTD contains all HTML elements and attributes, but does NOT INCLUDE presentational or deprecated elements (like font). Framesets are not allowed.
Transitional : This DTD contains all HTML elements and attributes, INCLUDING presentational and deprecated elements (like font). Framesets are not allowed.
What are New Semantic/Structural Elements
HTML5 offers new elements for better structure:
Tag Description
<article> Defines an article
<aside> Defines content aside from the page content
<bdi> Isolates a part of text that might be formatted in a different direction from other text outside it
<command> Defines a command button that a user can invoke
<details> Defines additional details that the user can view or hide
<dialog> Defines a dialog box or window
<summary> Defines a visible heading for a <details> element
<figure> Specifies self-contained content, like illustrations, diagrams, photos, code listings, etc.
<figcaption> Defines a caption for a <figure> element
<footer> Defines a footer for a document or section
<header> Defines a header for a document or section
<hgroup> Groups a set of <h1> to <h6> elements when a heading has multiple levels
<mark> Defines marked/highlighted text
<meter> Defines a scalar measurement within a known range (a gauge)
<nav> Defines navigation links
<progress> Represents the progress of a task
<ruby> Defines a ruby annotation (for East Asian typography)
<rt> Defines an explanation/pronunciation of characters (for East Asian typography)
<rp> Defines what to show in browsers that do not support ruby annotations
<section> Defines a section in a document
<time> Defines a date/time
<wbr> Defines a possible line-break

1. What is the difference between HTML and HTML5 ?
Ans: HTML5 is nothing more then upgraded 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

2. What is the <!DOCTYPE> ? Is it necessary to use in HTML5 ?
Ans: 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).

3. How many New Markup Elements you know in HTML5
Ans: Below are the New Markup Elements added in HTML5
Tag Description
<article> Specifies independent, self-contained content, could be a news-article, blog post, forum post,
or other articles which can be distributed independently from the rest of the site.
<aside> For content aside from the content it is placed in. The aside content should
be related to the surrounding content
<bdi> For text that should not be bound to the text-direction of its parent elements
<command> A button, or a radiobutton, or a checkbox
<details> For describing details about a document, or parts of a document
<summary> A caption, or summary, inside the details element
<figure> For grouping a section of
stand-alone content, could be a video
<figcaption> The caption of the figure section
<footer> For a footer of a document or section, could include the name of the author, the
date of the document, contact information, or copyright information
<header> For an introduction of a document or section, could include navigation
<hgroup> For a section of headings, using <h1> to <h6>, where the largest is the main
heading of the section, and the others are sub-headings
<mark> For text that should be highlighted
<meter> For a measurement, used only if the maximum and minimum values are known
<nav> For a section of navigation
<progress> The state of a work in progress
<ruby> For ruby annotation (Chinese notes or characters)
<rt> For explanation of the ruby annotation
<rp> What to show browsers that do not support the ruby element
<section> For a section in a document. Such as chapters, headers, footers, or any
other sections of the document
<time> For defining a time or a date, or both
<wbr> Word break. For defining a line-break opportunity.

4. What are the New Media Elements in HTML5? is canvas element used in HTML5
Ans: Below are the New Media Elements have added in HTML5
Tag Description
<audio> For multimedia content, sounds, music or other audio streams
<video> For video content, such as a movie clip or other video streams
<source> For media resources for media elements, defined inside video or audio
elements
For embedded content, such as a plug-in
<track> For text tracks used in mediaplayers
we can use Canvas element in html5 like <canvas></canvas>

5. Do you know New Input Type Attribute in HTML5
Ans: 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

6. How to add video and audio in HTML5
Ans: The canvas element is used to draw graphics images on a web page by using javascript like below
Like below we can add video in html5
1. <video width=“320″ height=“240″ controls=“controls”>
2. <source src=“mysong.mp4″ type=“video/mp4″ />
3. <source src=“mysong.ogg” type=“video/ogg” />
4. </video>
And audio like this
1. <audio controls=“controls”>
2. <source src=“mysong.ogg” type=“audio/ogg” />
3. <source src=“mysong.mp3″ type=“audio/mpeg” />
4. </audio>

7. What is the use of localStorage in HTML5?
Ans: 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
1. <script type=“text/javascript”>
2. localStorage.name=“PHPZAG”;
3. document.write(localStorage.name);
4. </script>
5. <script type=“text/javascript”>
6. localStorage.address=“Newyork USA”;
7. document.write(localStorage.address);
8. </script>

8. What is the sessionStorage Object in html5 ? How to create and access?
Ans: 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
1. <script type=“text/javascript”>
2. sessionStorage.name=“PHPZAG”;
3. document.write(sessionStorage.name);
4. </script>

9. What the use of Canvas Element in HTML5?
Ans: The canvas element is used to draw graphics images on a web page by using javascript like below
1. <canvas id=“pcdsCanvas” width=“500″ height=“400″>
2. </canvas>
3. <script type=“text/javascript”>
4. var pcdsCanvas=document.getElementById(“phpzagCanvas”);
5. var pcdsText=pcdsCanvas.getContext(“2d”);
6. pcdsText.fillStyle=“#82345c”;
7. pcdsText.fillRect(0,0,150,75);
8. </script>

10. What purpose does HTML5 serve?
Ans: HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silverlight, Apache Pivot, and Sun JavaFX.

11. What is the difference between HTMl5 Application cache and regular HTML browser cache?
Ans: HTML5 specification allows browsers to prefetch some or all of a website assets such as HTML files, images, CSS, JavaScript, and so on, while the client is connected. It is not necessary for the user to have accessed this content previously, for fetching this content. In other words, application cache can prefetch pages that have not been visited at all and are thereby unavailable in the regular browser cache. Prefetching files can speed up the site’s performance, though you are of course using bandwidth to download those files initially.

12. HOW DO YOU PLAY A AUDIO USING HTML5?
Ans:
We can display audio using the tag as shown below:
1. <audio controls=“controls”>
2. <source src=“test.mp3″ type=“audio/mp3″ />
3. </audio>

13. WHAT ARE THE DIFFERENT TYPES OF STORAGE IN HTML5?
Ans:
HTML5 offers two new objects for storing data on the client:
LocalStorage – stores data with no time limit
1. <script type=“text/javascript”>
2. localStorage.lastname=“ZAG”;
3. document.write(localStorage.lastname);
4. </script>
SessionStorage – stores data for one session.The data is deleted when the user closes the browser window.
1. <script type=“text/javascript”>
2. sessionStorage.lastname=“ZAG”;
3. document.write(sessionStorage.lastname);
4. </script>

14. HOW DO YOU PLAY A VIDEO USING HTML5?
Ans:
We can display video using the tag as shown below:
1. <video width=“320″ height=“240″ controls=“controls”>
2. <source src=“test.mp4″ type=“video/mp4″ />
3. </video>

15. WHAT ARE THE NEW APIS PROVIDED BY THE HTML 5 STANDARD? GIVE A BRIEF DESCRIPTION OF EACH?Ans:
The canvas element: Canvas consists of a drawable region defined in HTML code with height and width attributes. JavaScript code may access the area through a full set of drawing functions similar to other common 2D APIs, thus allowing for dynamically generated graphics. Some anticipated uses of the canvas include building graphs, animations, games, and image composition.
• Timed media playback
• Offline storage database
• Document editing
• Drag-and-drop
• Cross-document messaging
• Browser history management
• MIME type and protocol handler registration

16. WHAT OTHER ADVANTAGES DOES HTML5 HAVE?Ans:
a) Cleaner markup
b) Additional semantics of new elements like <header>, <nav>, and <time>
c) New form input types and attributes that will (and in Opera’s case, do) take the hassle out of scripting forms.

17.  GIVE AN EXAMPLE OF NEW ELEMENTS IN HTML5 TO SUPPORT MULTIMEDIA AND GRAPHICS?
Ans: HTML5 introduced many elements such as , instead of

19. WHAT IS THE DIFFERENCE BETWEEN HTML5 APPLICATION CACHE AND REGULATE HTML BROWSER CACHE?Ans:
The new HTML5 specification allows browsers to prefetch some or all of a website assets such as HTML files, images, CSS, JavaScript, and so on, while the client is connected. It is not necessary for the user to have accessed this content previously, for fetching this content. In other words, application cache can prefetch pages that have not been visited at all and are thereby unavailable in the regular browser cache. Prefetching files can speed up the site’s performance, though you are of course using bandwidth to download those files initially.

20. WHAT PURPOSE DOES HTML5 SERVE?
Ans:
HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silver light, Apache Pivot, and Sun JavaFX.

21.  WHAT IS THE STATUS OF THE DEVELOPMENT OF THE HTML 5 STANDARD?Ans: HTML5 is being developed as the next major revision of HTML (HyperText Markup Language), the core markup language of the World Wide Web. The Web Hypertext Application Technology Working Group (WHATWG) started work on the specification in June 2004 under the name Web Applications 1.0.[1] As of March 2010[update], the specification is in the Draft Standard state at the WHATWG, and in Working Draft state at the W3C.

What is HTML5?Ans : HTML5 is The New HTML Standard with new elements, attributes, and behaviors.
———————————————————————————————-
HTML 5 Features:Ans :
1. The <canvas> element for 2D drawing
2. The <video> and <audio> elements for media playback
3. local storage support.
4. Added New elements, like <figure>,<small>, <header>, <nav>,<article>, <footer>, <section>,<mark>
5. New form controls, like placeholder,calendar, date, time, email, url, search,required ,autofocus
6. In HTML5 there is only one <!doctype> declaration: <!DOCTYPE html>
———————————————————————————————-
What is HTML5 Web Storage?Ans : In HTML5, we can store data locally within the user’s browser.It is possible to store large amounts of data without affecting the website’s performance.
Web Storage is more secure and faster.
there are two types of Web Storages
1.LocalStorage:stores data locally with no limit
2.SessionStorage:stores data for one session
———————————————————————————————-
How to store data on client in HTML5?
Ans : we can store data using HTML5 Web Storage.
1.LocalStorage
<script type=”text/javascript”>
localStorage.name=”Raj”;
document.write(localStorage.name);
</script>
2.SessionStorage
<script type=”text/javascript”>
sessionStorage.email=”test@gmail.com”;
document.write(sessionStorage.email);
</script>
———————————————————————————————-
How do you play a Video using HTML5?
Ans : HTML5 defines a new element to embed a video on Web Page
the <video> element.
Example:
<video width=”500″ height=”300″ controls>
<source src=”video1.mp4″ type=”video/mp4″>
</video>
———————————————————————————————-
How do you play a Audio using HTML5?
Ans : HTML5 defines a new element to embed a video on Web Page
the <audio> element.
Example:
<audio controls>
<source src=”audio.mp3″ type=”audio/mpeg”>
</audio>
———————————————————————————————-
Canvas Element in HTML5?
Ans : The canvas element is used to draw graphics images on a web page
<canvas id=”canvas_image” width=”400″ height=”200″></canvas>
The canvas is a two-dimensional grid.
———————————————————————————————-
HTML5 <input> Types ?
Ans :
• search
• tel
• time
• color
• email
• month
• date
• datetime
• datetime-local
• number
• range
• url
• week
———————————————————————————————-
HTML5 New Form Attributes?Ans :
• pattern
• placeholder
• required
• step
• autocomplete
• autofocus
• height and width
• list
• min and max
• multiple
• form
• formaction
• formenctype
• formmethod
• formnovalidate
• formtarget
———————————————————————————————-
What does a <hgroup> tag do?
Ans : The <hgroup> tag is used to group heading elements.
The <hgroup> element is used to group a set of <h1> to <h6> elements.
<hgroup>
<h1>Hello</h1>
<h2>How r u?</h2>
</hgroup>
———————————————————————————————-
Which video formats are used for the video element?Ans :
Internet Explorer 9+: MP4
Chrome 6+: MP4, WebM, Ogg
Firefox 3.6+ : WebM, Ogg
Safari 5+ : MP4,
Opera 10.6+ : WebM,Ogg
———————————————————————————————-
Difference between HTML4 and HTML5 
———————————————————————————————-
What is the <!DOCTYPE> ? Is it necessary to use in HTML5 ?
Ans : The <!DOCTYPE> declaration must be the very first thing in HTML5 document, before the <html> tag
———————————————————————————————-
What are the New Media Elements in HTML5?Ans :
• <audio>
• <video>
• <source>

• <track>
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