CSS Interview Questions and Answers

Question - 61 : - How do I make my div 100% height?

Answer - 61 : - 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.

Question - 62 : - What is property?

Answer - 62 : - Property is a stylistic parameter (attribute) that can be influenced through CSS, e.g. FONT or WIDTH. There must always be a corresponing value or values set to each property, e.g. font: bold or font: bold san-serif.

Question - 63 : - How do I write my style sheet so that it gracefully cascades with user's personal sheet ?

Answer - 63 : - 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.

Question - 64 : - What are pseudo-elements?

Answer - 64 : - 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. Pseudo-element is created by a colon followed by pseudo-element's name, e.g: P:first-line H1:first-letter and can be combined with normal classes; e.g: P.initial:first-line First-line pseudo-element allows sub-parting the element's first line and attaching specific style exclusively to this sub-part; e.g.: P.initial:first-line {text-transform: uppercase}

The first line of this paragraph will be displayed in uppercase letters

First-letter pseudo-element allows sub-parting the element's first letter and attaching specific style exclusively to this sub-part; e.g.: P.initial:first-letter { font-size: 200%; color: red}

The first letter of this paragraph will be displayed in red and twice as large as the remaining letters

As a developer who works with CSS every day, I find one complication that continues to bother me in my daily work. Support for CSS has always been good on the horizontal scope, but vertical positioning has always been quite complicated. Alone the procedure to affix a footer to the bottom of a screen in dependance of the amount of content is unnecessarily difficult. The old table method provided much easier methods for this. What are your thoughts on this and do you see improvement following in future CSS revisions? Indeed, the CSS formatting model allows more control horizontally than vertically. This is due to (typically) having a known width, but an unknown height. As such, the height is harder to deal with. However, CSS2 fixed positioning allows you to place content relative to the viewport (which is CSS-speak for window) instead of the document. For example, by setting position: fixed; bottom: 0 on an element, it will stick to the

Question - 65 : - How can I make a page look the same in e.g. NS and MSIE ?

Answer - 65 : - 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.

Question - 66 : - Is there anything that CAN'T be replaced by Style Sheets?

Answer - 66 : - 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 CSS1 specification 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 contents should be displayed, then some or all of its functionality has been absorbed by style sheets.  

Question - 67 : - Can I include comments in my Style Sheet?

Answer - 67 : - 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.

Question - 68 : - What is the difference between ID and CLASS?

Answer - 68 : - ID identifies and sets style to one and only one occurrence of an element while class can be attached to any number of elements. By singling out one occurrence of an element the unique value can be declared to said element.

Question - 69 : - How to make text-links without underline?

Answer - 69 : - a:link, a:visited {text-decoration: none} or ...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 Both background and foreground colors should be specified as the property that is not specified can be overridden by user's own settings.

Question - 70 : - How do you make a tool tip that appears on hover?

Answer - 70 : - The most simple way is to use the 'title' attribute like this... HTML like this CSS a.tooltip { position:relative; cursor:help; } a.tooltip span { display: none; position:absolute; top:1.5em; left:0; width:15em; padding:0 2px; } a.tooltip:hover { display:inline; } a.tooltip:hover span { display:block; border:1px solid gray; background-color:white; } HTML Karl Marx-info goes here- Without this part... a.tooltip:hover { display:inline; } ..it won't work in IE. The "#n" in the link is to prevent the page from jumping to the top if the link is clicked. The "href" part is necessary as it won't work in IE without it.