Wednesday 25 April 2018

CSS Interview Question

1. What Is The Difference Between Id And Class?

ID identifies and sets style to one and only one occurrence of an element while class can be attached to any number of elements.

2. Can I Include Comments In My Style Sheet?

Yes. Comments can be written anywhere where whitespace is allowed and are treated as white space themselves. Anything written between /* and */ is treated as a comment (white space).
NOTE: Comments cannot be nested.

3. Is There Anything That Can T Be Replaced By Style Sheets?

Quite a bit actually. Style sheets only specify information that controls display and rendering information. Virtual style elements that convey the NATURE of the content can not be replaced by style sheets, and hyperlinking and multimedia object insertion is not a part of style sheet functionality at all (although controlling how those objects appear IS part of style sheets functionality.) The CSS1specification has gone out of its way to absorb ALL of the HTML functionality used in controlling display and layout characteristics. For more information on the possible properties in CSS, see the Index DOT Css Property Index.
Rule of Thumb: if an HTML element or attribute gives cues as to how its contentsshould be displayed, then some or all of its functionality has been absorbed by stylesheets.

4. How Can I Make A Page Look The Same In E.g. Ns And Msie ?

The simple answer is, you can't, and you shouldn't waste your time trying to make it exactly the same. Web browsers are allowed, per definition, to interpret a page as they like, subject to the general rules set down in the HTML and CSS specifications. As a web author you can not have a prior knowledge of the exact situation and/or medium that will be used to render your page, and it's almost always rather counterproductive to try to control that process. There is no necessity for a well-written page to look the same in different browsers. You may want to strive to ensure that it looks good in more than one browser, even if the actual display (in the case of graphical browsers) comes out a bit different. "Looking good" can be achieved by adopting sensible design and guidelines, such as not fixing the size or face of your fonts, not fixing the width of tables, etc… Don't fight the medium; most web users only use one browser and will never know, or bother to find out, that your page looks different, or even "better", in any other browser.

5. What Are Pseudo-elements?

Pseudo-elements are fictional elements that do not exist in HTML. They address the element's sub-part (non-existent in HTML) and not the element itself. In CSS1 there are two pseudo-elements: 'first-line pseudo-element' and 'first-letter pseudo-element'. They can be attached to block-level elements (e.g. paragraphs or headings) to allow typographical styling of their sub-parts.

6. How Do I Write My Style Sheet So That It Gracefully Cascades With User S Personal Sheet ?

You can help with this by setting properties in recommended places. Style rules that apply to the whole document should be set in the BODY element -- and only there. In this way, the user can easily modify document-wide style settings.

7. What Is Property?

Property is a stylistic parameter (attribute) that can be influenced through CSS, e.g. FONT or WIDTH. There must always be a corresponding value or values set to each property, e.g. font: bold or font: bold san-serif.

8. What Can Be Done With Style Sheets That Can Not Be Accomplished With Regular Html?

Many of the recent extensions to HTML have been tentative and somewhat crude attempts to control document layout. Style sheets go several steps beyond, and introduces complex border, margin and spacing control to most HTML elements. It also extends the capabilities introduced by most of the existing HTML browser extensions. Background colors or images can now be assigned to ANY HTMLelement instead of just the BODY element and borders can now be applied to anyelement instead of just to tables. For more information on the possible properties in CSS, see the Index DOT Css Property Index.

9. Why Is My External Stylesheet Not Working ?

There may be several different reasons behind that, but one very common mistake is to have an external stylesheet that contains HTML markup in some form.
An external stylesheet must contain only CSS rules, and if required, correctly formed CSS comments; never include any HTML syntax, such as <style type="text/css">…
CSS comments are defined as anything that is placed between
/* (the comment start mark) and
*/ (the comment end mark). I.e. as follows…
/* This text right here is a correct CSS comment */
CSS comments may span multiple lines in the stylesheet. Nesting of CSS comments is not allowed.
Another reason for external stylesheets (and even embedded and inline stylerules) not to function as expected may be that you have tried to make use of some CSS-features that are not supported in the browser you are using.
External stylesheets shall also be served from the www-server with a MIME-type of 'text/css' in its 'Content Type:' HTTP header.
You may need to negotiate with your server admin to add this MIME type to your server if you are not able to configure the server yourself.

10. How Do I Quote Font Names In Quoted Values Of The Style Attribute?

The attribute values can contain both single quotes and double quotes as long as they come in matching pairs. If two pair of quotes are required include single quotes in double ones or vice versa:
<P STYLE="font-family: 'New Times Roman'; font-size: 90%">
<P STYLE='font-family: "New Times Roman"; font-size: 90%'>
It's been reported the latter method doesn't work very well in some browsers, therefore the first one should be used.

11. Styles Not Showing?

There are different ways to apply CSS to a HTML document with a stylesheet, and these different ways can be combined:
* inline (internal) (Deprecated for XHTML)
* embedded (internal)
* linked (external) and
* @import (external)
Note: An external stylesheet is a text file that contains only CSS Styles. HTML comments are not supposed to be in there and can lead to misinterpretation (> is the CSS "Child" selector!).

12. Are Style Sheets Case Sensitive?

No. Style sheets are case insensitive. Whatever is case insensitive in HTML is also case insensitive in CSS. However, parts that are not under control of CSS like font family names and URLs can be case sensitive - IMAGE.gif and image.gif is not the same file.

13. What Is Cascade?

Cascade is a method of defining the weight (importance) of individual styling rules thus allowing conflicting rules to be sorted out should such rules apply to the sameselector.
Declarations with increased weight take precedence over declaration with normal weight:
P {color: white ! important} /* increased weight */
P (color: black} /* normal weight */

14. What Is Important Declaration?

Important declaration is a declaration with increased weight. Declaration with increased weight will override declarations with normal weight. If both reader's and author's style sheet contain statements with important declarations the author's declaration will override the reader's.
BODY {background: white ! important; color: black}
In the example above the background property has increased weight while the color property has normal.

15. What Is Css Declaration?

CSS declaration is style attached to a specific selector. It consists of two parts; property which is equivalent of HTML attribute, e.g. text-indent: and value which is equivalent of HTML value, e.g. 10pt. NOTE: properties are always ended with a colon.

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