CSS Interview Questions


Dear readers, these CSS Interview Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your interview for the subject of CSS Language. As per my experience good interviewers hardly plan to ask any particular question during your interview, normally questions start with some basic concept of the subject and later they continue based on further discussion and what you answer:

Cascading Style Sheets, fondly referred to as CSS, is a simple design language intended to simplify the process of making web pages presentable.

Following are the advantages of using CSS −

  • CSS saves time − You can write CSS once and then reuse same sheet in multiple HTML pages. You can define a style for each HTML element and apply it to as many Web pages as you want.

  • Pages load faster − If you are using CSS, you do not need to write HTML tag attributes every time. Just write one CSS rule of a tag and apply it to all the occurrences of that tag. So less code means faster download times.

  • Easy maintenance − To make a global change, simply change the style, and all elements in all the web pages will be updated automatically.

  • Superior styles to HTML − CSS has a much wider array of attributes than HTML, so you can give a far better look to your HTML page in comparison to HTML attributes.

  • Multiple Device Compatibility − Style sheets allow content to be optimized for more than one type of device. By using the same HTML document, different versions of a website can be presented for handheld devices such as PDAs and cell phones or for printing.

  • Global web standards − Now HTML attributes are being deprecated and it is being recommended to use CSS. So its a good idea to start using CSS in all the HTML pages to make them compatible to future browsers.

  • Offline Browsing − CSS can store web applications locally with the help of an offline catche.Using of this, we can view offline websites.The cache also ensures faster loading and better overall performance of the website.

  • Platform Independence − The Script offer consistent platform independence and can support latest browsers as well.

A style rule is made of three parts −

  • Selector − A selector is an HTML tag at which a style will be applied. This could be any tag like <h1> or <table> etc.

  • Property − A property is a type of attribute of HTML tag. Put simply, all the HTML attributes are converted into CSS properties. They could be color, border etc.

  • Value − Values are assigned to properties. For example, color property can have value either red or #F1F1F1 etc.

Type selector quite simply matches the name of an element type. To give a color to all level 1 headings −

h1 {
   color: #36CFFF; 
}

Rather than selecting elements of a specific type, the universal selector quite simply matches the name of any element type −

* { 
   color: #000000; 
}

This rule renders the content of every element in our document in black.

Suppose you want to apply a style rule to a particular element only when it lies inside a particular element. As given in the following example, style rule will apply to <em> element only when it lies inside <ul> tag.

ul em {
   color: #000000; 
}

You can define style rules based on the class attribute of the elements. All the elements having that class will be formatted according to the defined rule.

.black {
   color: #000000; 
}

This rule renders the content in black for every element with class attribute set to black in our document.

You can make it a bit more particular. For example −

h1.black {
   color: #000000; 
}

This rule renders the content in black for only <h1> elements with class attribute set to black.

You can define style rules based on the id attribute of the elements. All the elements having that id will be formatted according to the defined rule.

#black {
   color: #000000; 
}

This rule renders the content in black for every element with id attribute set to black in our document.

ou can make it a bit more particular. For example −

h1#black {
   color: #000000; 
}

This rule renders the content in black for only <h1> elements with id attribute set to black.

Consider the following example −

body > p {
   color: #000000; 
}

This rule will render all the paragraphs in black if they are direct child of <body> element. Other paragraphs put inside other elements like <div> or <td> would not have any effect of this rule.

You can also apply styles to HTML elements with particular attributes. The style rule below will match all the input elements having a type attribute with a value of text −

input[type = "text"] {
   color: #000000; 
}

The advantage to this method is that the <input type = "submit" /> element is unaffected, and the color applied only to the desired text fields.

p[lang] : Selects all paragraph elements with a lang attribute.

p[lang="fr"] - Selects all paragraph elements whose lang attribute has a value of exactly "fr".

p[lang~="fr"] - Selects all paragraph elements whose lang attribute contains the word "fr".

p[lang|="en"] - Selects all paragraph elements whose lang attribute contains values that are exactly "en", or begin with "en-".

There are four ways to associate styles with your HTML document. Most commonly used methods are inline CSS and External CSS.

  • Embedded CSS − The <style> Element: You can put your CSS rules into an HTML document using the <style> element.

  • Inline CSS − The style Attribute: You can use style attribute of any HTML element to define style rules.

  • External CSS − The <link> Element: The <link> element can be used to include an external stylesheet file in your HTML document.

  • Imported CSS − @import Rule: @import is used to import an external stylesheet in a manner similar to the <link> element.

Following is the rule to override any Style Sheet Rule −

  • Any inline style sheet takes highest priority. So, it will override any rule defined in <style>...</style> tags or rules defined in any external style sheet file.

  • Any rule defined in <style>...</style> tags will override rules defined in any external style sheet file.

  • Any rule defined in external style sheet file takes lowest priority, and rules defined in this file will be applied only when above two rules are not applicable.

% - Defines a measurement as a percentage relative to another value, typically an enclosing element.

p {font-size: 16pt; line-height: 125%;}

cm − Defines a measurement in centimeters.

div {margin-bottom: 2cm;}

em − A relative measurement for the height of a font in em spaces. Because an em unit is equivalent to the size of a given font, if you assign a font to 12pt, each "em" unit would be 12pt; thus, 2em would be 24pt.

p {letter-spacing: 7em;}

ex − This value defines a measurement relative to a font's x-height. The x-height is determined by the height of the font's lowercase letter.

p {font-size: 24pt; line-height: 3ex;}

in − Defines a measurement in inches.

p {word-spacing: .15in;}

mm − Defines a measurement in millimeters.

p {word-spacing: 15mm;}

pc − Defines a measurement in picas. A pica is equivalent to 12 points; thus, there are 6 picas per inch.

p {font-size: 20pc;}

pt − Defines a measurement in points. A point is defined as 1/72nd of an inch.

body {font-size: 18pt;}

px − Defines a measurement in screen pixels.

p {padding: 25px;}

vh − 1% of viewport height.

h2 { font-size: 3.0vh; }

vw − 1% of viewport width.

h1 { font-size: 5.9vw; } 

vmin 1vw or 1vh, whichever is smaller.

p { font-size: 2vmin;}

You can specify your color values in various formats. Following table lists all the possible formats −

Format Syntax Example
Hex Code #RRGGBB p{color:#FF0000;}
Short Hex Code #RGB p{color:#6A7;}
RGB % rgb(rrr%,ggg%,bbb%) p{color:rgb(50%,50%,50%);}
RGB Absolute rgb(rrr,ggg,bbb) p{color:rgb(0,0,255);}
keyword aqua, black, etc. p{color:teal;}

There is the list of 216 colors which are supposed to be most safe and computer independent colors. These colors vary from hexa code 000000 to FFFFFF. These colors are safe to use because they ensure that all computers would display the colors correctly when running a 256 color palette.

The background-color property is used to set the background color of an element.

The background-image property is used to set the background image of an element.

The background-repeat property is used to control the repetition of an image in the background.

The background-position property is used to control the position of an image in the background.

The background-attachment property is used to control the scrolling of an image in the background.

The background property is used as a shorthand to specify a number of other background properties.

The font-family property is used to change the face of a font.

The font-style property is used to make a font italic or oblique.

The font-variant property is used to create a small-caps effect.

The font-weight property is used to increase or decrease how bold or light a font appears.

The font-size property is used to increase or decrease the size of a font.

The font property is used as shorthand to specify a number of other font properties.

The color property is used to set the color of a text.

The direction property is used to set the text direction.

The letter-spacing property is used to add or subtract space between the letters that make up a word.

The word-spacing property is used to add or subtract space between the words of a sentence.

The text-indent property is used to indent the text of a paragraph.

The text-align property is used to align the text of a document.

The text-decoration property is used to underline, overline, and strikethrough text.

The text-transform property is used to capitalize text or convert text to uppercase or lowercase letters.

The white-space property is used to control the flow and formatting of text.

The text-shadow property is used to set the text shadow around a text.

The border property is used to set the width of an image border.

The height property is used to set the height of an image.

The width property is used to set the width of an image.

The -moz-opacity property is used to set the opacity of an image.

The :link signifies unvisited hyperlinks.

The :visited signifies visited hyperlinks.

The :hover signifies an element that currently has the user's mouse pointer hovering over it.

The :active signifies an element on which the user is currently clicking.

The border-collapse specifies whether the browser should control the appearance of the adjacent borders that touch each other or whether each cell should maintain its style.

The border-spacing specifies the width that should appear between table cells.

The caption-side captions are presented in the <caption> element. By default, these are rendered above the table in the document. You use the caption-side property to control the placement of the table caption.

The empty-cells specifies whether the border should be shown if a cell is empty.

The table-layout allows browsers to speed up layout of a table by using the first width properties it comes across for the rest of a column rather than having to load the whole table before rendering it.

The border-color specifies the color of a border.

The border-style specifies whether a border should be solid, dashed line, double line, or one of the other possible values.

The border-width specifies the width of a border.

The margin specifies a shorthand property for setting the margin properties in one declaration.

The margin-bottom specifies the bottom margin of an element.

The margin-top specifies the top margin of an element.

The margin-left specifies the left margin of an element.

The margin-right specifies the right margin of an element.

The list-style-type allows you to control the shape or appearance of the marker.

The list-style-position specifies whether a long point that wraps to a second line should align with the first line or start underneath the start of the marker.

The list-style-image specifies an image for the marker rather than a bullet point or number.

The list-style serves as shorthand for the styling properties.

The marker-offset specifies the distance between a marker and the text in the list.

The padding-bottom specifies the bottom padding of an element.

The padding-top specifies the top padding of an element.

The padding-left specifies the left padding of an element.

The padding-right specifies the right padding of an element.

The padding serves as shorthand for the all the padding properties.

The cursor property of CSS allows you to specify the type of cursor that should be displayed to the user.

auto − Shape of the cursor depends on the context area it is over. For example, an 'I' over text, a 'hand' over a link, and so on.

crosshair − A crosshair or plus sign.

default − An arrow.

pointer − A pointing hand (in IE 4 this value is hand).

move or text − The 'I' bar.

wait − An hour glass.

help − A question mark or balloon, ideal for use over help buttons.

Yes! set the url as the source of a cursor image file.

The outline-width property is used to set the width of the outline.

The outline-style property is used to set the line style for the outline.

The outline-color property is used to set the color of the outline.

The outline property is used to set all the outlining properties in a single statement.

The height property is used to set the height of a box.

The width property is used to set the width of a box.

What is Next ?

Further you can go through your past assignments you have done with the subject and make sure you are able to speak confidently on them. If you are fresher then interviewer does not expect you will answer very complex questions, rather you have to make your basics concepts very strong.

Second it really doesn't matter much if you could not answer few questions but it matters that whatever you answered, you must have answered with confidence. So just feel confident during your interview. We at tutorialspoint wish you best luck to have a good interviewer and all the very best for your future endeavor. Cheers :-)

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