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CSS Interview Questions Answers

CSS Interview Question - 1 : -

How do I have a background image that isn't tiled?

CSS Interview Answer - 1 : -

Specify the background-repeat property as no-repeat. You can also use the background property as a shortcut for specifying multiple background-* properties at once. Here's an example:

BODY {background: #FFF url(watermark.jpg) no-repeat;}

 

CSS Interview Question - 2 : -

Why does Netscape lose my styles ?

CSS Interview Answer - 2 : -

Netscape 4.x has poor support for CSS. Having said that, the following points should be noted.
Invalid HTML will almost certainly cause Netscape to ignore your CSS suggestions at some point. You will find that valid HTML is your best friend, but for Netscape to work properly you must ensure that all elements in your markup which permit closing tags are explicitly closed.
Check and correct your CSS suggestions for the very same reason, Netscape 4.x is in fact doing "the right thing", as per CSS specs (as opposed to MSIE) when it ignores style rules with errors.
Netscape 4.x has what's called an "inheritance problem" into its TABLE element. It can be argued that NS is all within its right to behave as it does in this case, but since the workaround is quite simple it's easy enough to just use it and be done with it.
Let's say you want your TABLE content to "look the same" as your BODY content? "Redundant" styling comes to your help as in e.g. BODY, TABLE, TH, TD { /* insert your styles here */ }
On a generic level, Netscape 4.x likes to have style rules applied directly to the elements where they are needed. You can never really trust the inheritance principle to work correctly at any level in Netscape 4.x.
 

CSS Interview Question - 3 : -

How to make text-links without underline?

CSS Interview Answer - 3 : -

a:link, a:visited {text-decoration: none}

or

<a style="text-decoration: none" HREF="...">

...will show the links without underlining. However, suppressing the underlining of links isn't a very smart idea as most people are used to having them underlined. Also, such links are not spotted unless someone coincidentally runs a mouse over them. If, for whatever reason, links without underline are required background and foreground colors can be instead declared to them so that they can be distinguished from other text, e.g.;

a:link, a:visited {text-decoration: none; background: red; color: blue}

or

<a style="text-decoration: none; background: red; color: blue" HREF="...">

Both background and foreground colors should be specified as the property that is not specified can be overridden by user's own settings.

 

CSS Interview Question - 4 : -

CSS is clearly very useful for separating style from content. But apparently people tend to have problems when using it for layouts. Would you say this is because people have not yet understood how to properly do layout in CSS, or is it CSS that is lacking in this area? What can be done to improve the situation? --- Would the web benefit from HTML and CSS being complemented with some kind of "layout language"?

CSS Interview Answer - 4 : -

Layout and style should be tackled by the same language and the two are intertwined. Trying to split the two is like splitting the HTML specification in two, one specification describing inline elements and the other describing block elements. It's not worth the effort. CSS is capable of describing beautiful and scalable layouts. The CSS Zen Garden has been a eye-opening showcase of what is possible today. If MS IE had supported CSS tables, another set of layouts would have been possible. So, there is still lots of potential in the existing CSS specifications which should be the next milestone.

I always wanted to have "included" substyles or "aliases" in my CSS definition, to save redundancy.
(For includes)

.class1 { color:#ff0000; }
.class2 { background-color:#ffffff; }
.class3 { include:class1,class2;font-weight:bold; }

(For aliases)

@alias color1 #ff0000;
@alias color2 #ffffff;
@alias default_image url('/img/image1.jpg');

.class1 { color:color1; }
.class2 { background-image:default_image;background-color:co lor2; }

This way we could change colors or images for a whole webpage
by editing a reduced number of lines.

 

CSS Interview Question - 5 : -

How do I quote font names in quoted values of the style attribute?

CSS Interview Answer - 5 : -

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.

 

CSS Interview Question - 6 : -

Can CSS be used with other than HTML documents?

CSS Interview Answer - 6 : -

Yes. CSS can be used with any ny structured document format. e.g. XML, however, the method of linking CSS with other document types has not been decided yet.
 

CSS Interview Question - 7 : -

What is CLASS selector?

CSS Interview Answer - 7 : -

Class selector is a "stand alone" class to which a specific style is declared. Using the CLASS attribute the declared style can then be associated with any HTML element. The class selectors are created by a period followed by the class's name. The name can contain characters a-z, A-Z, digits 0-9, period, hyphen, escaped characters, Unicode characters 161-255, as well as any Unicode character as a numeric code, however, they cannot start with a dash or a digit. (Note: in HTML the value of the CLASS attribute can contain more characters).It is a good practice to name classes according to their function than their appearance.

.footnote {font: 70%} /* class as selector */

<ADDRESS CLASS=footnote/>This element is associated with the CLASS footnote</ADDRESS>
<P CLASS=footnote>And so is this</P>

 

CSS Interview Question - 8 : -

How do I make my div 100% height?

CSS Interview Answer - 8 : -

You need to know what the 100% is of, so the parent div must have a height set. One problem that people often come up against is making the main page fill the screen if there's little content. You can do that like this :
CSS
body, html {
height:100%;
}
body {
margin:0;
padding:0;
}
#wrap {
position:relative;
min-height:100%;
}
* html #wrap {
height:100%;
}

Here, the #wrap div goes around your whole page - it's like a sub-body.

You need to use 'min-height' rather than 'height' for Firefox because otherwise it will set it to 100% of the viewport and no more. Internet Explorer, being well... crap, treats 'height' as it should be treating 'min-height' which it doesn't recognise. (You can target IE by preceding your code with ' * html ').

To make floated divs within this #wrap div 100% of the #wrap div... well that's more difficult. I think the best way is to use the 'faux columns' technique which basically means that you put the background in your body rather than your columns. If the body has columns and your floats don't then it looks like your floated content is in a column that stretches to the bottom of the page. I've used this technique in my layout demos.

The problem is often not that the columns aren't 100% height, but that they're not equal lengths. Columns usually don't start from the top of the page and end at the bottom - there's often a header and a footer or sometimes, more interesting designs don't have a recognisable columnar layout, but do require div boxes to be equal heights. This can be done with the aid of a couple of images and some css or with some javascript.

 

CSS Interview Question - 9 : -

What does the "Cascading" in "Cascading Style Sheets" mean?

CSS Interview Answer - 9 : -

Style Sheets allow style information to be specified from many locations. Multiple (partial) external style sheets can be referenced to reduce redundancy, and both authors as well as readers can specify style preferences. In addition, three main methods can be employed by an author to add style information to HTML documents, and multiple approaches for style control are available in each of these methods. In the end, style can be specified for a single element using any, or all, of these methods. What style is to be used when there is a direct conflict between style specifications for an element?
Cascading comes to the rescue. A document can have styles specified using all of these methods, but all the information will be reduced to a single, cohesive "virtual" Style Sheet. Conflict resolution is based on each style rule having an assigned weight according to its importance in the scheme of things. A rule with a higher overall importance will carry a higher weight. This will be used in place of a competing style rule with a lower weight/importance. A hierarchy of competing styles is thus formed creating a "cascade" of styles according to their assigned weights. The algorithm used to determine this cascading weight scale is fairly complex.
 

CSS Interview Question - 10 : -

What is CSS rule 'ruleset'?

CSS Interview Answer - 10 : -

There are two types of CSS rules: ruleset and at-rule. Ruleset identifies selector or selectors and declares style which is to be attached to that selector or selectors. For example P {text-indent: 10pt} is a CSS rule. CSS rulesets consist of two parts: selector, e.g. P and declaration, e.g. {text-indent: 10pt}.

P {text-indent: 10pt} - CSS rule (ruleset)
{text-indent: 10pt} - CSS declaration
text-indent - CSS property
10pt - CSS value

 

CSS Interview Question - 11 : -

How do I have a fixed (non-scrolling) background image?

CSS Interview Answer - 11 : -

With CSS, you can use the background-attachment property. The background attachment can be included in the shorthand background property, as in this example:

body {
background: white url(example.gif) fixed ;
color: black ;
}

Note that this CSS is supported by Internet Explorer, Mozilla, Firefox Opera, Safari, and other browsers. In contrast, Microsoft's proprietary BGPROPERTIES attribute is supported only by Internet Explorer.

 

CSS Interview Question - 12 : -

When is auto different from 0 in margin properties?

CSS Interview Answer - 12 : -

In vertical margins, auto is always equal to 0. In horizontal margins, auto is only equal to 0 if the width property is also auto. Here are three examples, assume that there is a <P> that is a child of<BODY>:

Example 1: auto value on the width.

BODY {width: 30em;}
P {width: auto; margin-left: auto; margin-right: auto;}

Since the width property is auto, the auto values of the two margins will be ignored. The result is a P that is 30em wide, with no margins.

Example 2: two auto margins

BODY {width: 30em;}
P {width: 20em; margin-left: auto; margin-right: auto;}

The P will be 20em wide and the remaining 10em will be divided between the two margins. Paragraphs will be indented 5em at both sides.

Example 3: one auto margin

BODY {width: 30em;}
P {width: 20em; margin-left: 2em; margin-right: auto;}

In this case, paragraphs are 20em wide and are indented 2em on the left side. Since the total width available is 30em, that means the right margin will be 8em.
Note that the default value of width is auto, so setting one or both margins to auto is only useful if you set the width to something other than auto at the same time.

 

CSS Interview Question - 13 : -

What is Extensible Stylesheet Language (XSL)?

CSS Interview Answer - 13 : -

XSL is a proposed styling language for formatting XML (eXtensible Markup Language) documents. The proposal was submitted to the W3C by Microsoft, Inso, and ArborText.
 

CSS Interview Question - 14 : -

What is cascade?

CSS Interview Answer - 14 : -

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 same selector.

Declarations with increased weight take precedence over declaration with normal weight:

P {color: white ! important} /* increased weight */
P (color: black} /* normal weight */

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.

 

 

CSS Interview Question - 15 : -

Why use Style Sheets?

CSS Interview Answer - 15 : -

Style sheets allow a much greater degree of layout and display control than has ever been possible thus far in HTML. The amount of format coding necessary to control display characteristics can be greatly reduced through the use of external style sheets which can be used by a group of documents. Also, multiple style sheets can be integrated from different sources to form a cohesive tapestry of styles for a document. Style sheets are also backward compatible - They can be mixed with HTML styling elements and attributes so that older browsers can view content as intended.