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Category Archives: css tags

CSS3 new attribute selectors

Posted on November 19, 2012 - 7:51 am by

CSS3 introduce 3 new selectors for the sub-string or matching attributes. they are [att^=val], [att$=val] and [att*=val]. these selectors coming under Sub-string Matching Attribute Selectors section.

[att^=val]

This is the “begins with” selector. This selector allows for the selection of elements where a specified attribute begins with a specified string. example:

<pre>a[alt~=”Kerala”] { color:#00aa00; font-size:14px; border:1px solid #00aa00; padding:3px 10px; font-family:Arial, Helvetica, sans-serif;  text-decoration:none; margin:2px; background:#afa }</pre>

<code>a[alt~=”Karnataka”] { color:#0000aa; font-size:14px; border:1px solid #0000aa; padding:3px 10px; font-family:Arial, Helvetica, sans-serif; text-decoration:none; margin:2px; background:#aaf }</code>

CSS Positioning

Posted on December 11, 2009 - 11:33 am by
Position:Static

The default positioning for all elements is position:static, which means the element is not positioned and occurs where it normally would in the document.
Normally you wouldn’t specify this unless you needed to override a positioning that had been previously set.

#div-1 {   
position:static;  }

 

Position:Relative

If you specify position:relative, then you can use top or bottom, and left or right to move the element relative to where it would normally occur in the document.

Let’s move div-1 down 20 pixels, and to the left 40 pixels:

#div-1 {   
position:relative;
top:20px;
left:-40px;  }

Notice the space where div-1 normally would have been if we had not moved it: now it is an empty space. The next element (div-after) did not move when we moved div-1. That’s because div-1 still occupies that original space in the document, even though we have moved it.

It appears that position:relative is not very useful, but it will perform an important task later in this tutorial.

Position:Absolute

When you specify position:absolute, the element is removed from the document and placed exactly where you tell it to go.

Let’s move div-1a to the top right of the page:

#div-1a {   
position:absolute;   
top:0;   
right:0;   
width:200px;  }

Notice that this time, since div-1a was removed from the document, the other elements on the page were positioned differently: div-1b, div-1c, and div-after moved up since div-1a was no longer there.

Also notice that div-1a was positioned in the top right corner of the page. It’s nice to be able to position things directly the page, but it’s of limited value.

What I really want is to position div-1a relative to div-1. And that’s where relative position comes back into play.

Footnotes
  • There is a bug in the Windows IE browser: if you specify a relative width (like “width:50%”) then the width will be based on the parent element instead of on the positioning element.
Position:Relative + Position:Absolute

If we set relative positioning on div-1, any elements within div-1 will be positioned relative to div-1. Then if we set absolute positioning on div-1a, we can move it to the top right of div-1:

#div-1 {   
position:relative;  }  


#div-1a {   
position:absolute;   
top:0;   
right:0;   
width:200px;  }
Two Column Absolute

Now we can make a two-column layout using relative and absolute positioning!

#div-1 {   
position:relative;  }  


#div-1a {   
position:absolute;  
 top:0;   
right:0;   
width:200px;  } 


 #div-1b {   
position:absolute;  
 top:0;   
left:0;   
width:200px;  }

One advantage to using absolute positioning is that we can position the elements in any order on the page, regardless of the order they appear in the HTML. So I put div-1b before div-1a.

But wait – what happened to the other elements? They are being obscured by the absolutely positioned elements. What can we do about that?

 

float

For variable height columns, absolute positioning does not work, so let’s come up with another solution.

We can “float” an element to push it as far as possible to the right or to the left, and allow text to wrap around it. This is typically used for images, but we will use it for more complex layout tasks (because it’s the only tool we have).

#div-1a {   
float:left;  
 width:200px;  }
float columns

If we float one column to the left, then also float the second column to the left, they will push up against each other.

#div-1a {  
float:left;   
width:150px;  }  


#div-1b {   
float:left;   
width:150px;  }

float columns with clear

Then after the floating elements we can “clear” the floats to push down the rest of the content.

#div-1a {   
float:left;  
 width:190px;  }  


#div-1b {   
float:left;  
width:190px;  }  


#div-1c {   
clear:both;  }

Efficient CSS with shorthand properties

Posted on May 6, 2009 - 6:20 am by

Efficient CSS with shorthand properties

I get a lot of questions about CSS from people who aren’t crazy enough to have spent the thousands of hours working with CSS that I have. Sometimes I’m asked to take a look at something they’re working on to see if I can figure out why it doesn’t work as expected. When I look at their CSS I often find that it’s both bloated and unorganised.

One of the reasons for using CSS to layout websites is to reduce the amount of HTML sent to site visitors. To avoid just moving the bloat from HTML to CSS, you should try to keep the size of your CSS files down as well, and I thought I’d explain my favourite CSS efficiency trick: shorthand properties. Most people know about and use some shorthand, but many don’t make full use of these space saving properties.

Some background

Shorthand properties can be used to set several properties at once, in a single declaration, instead of using a separate declaration for each individual property. As you’ll see, this can save a lot of space in your CSS file.

Quite a few shorthand properties are available – for details I suggest the W3C CSS specifications of the background, border, border-color, border-style, border sides (border-top, border-right, border-bottom, border-left), border-width, font, list-style, margin, outline, and paddingproperties.

Colours

The most common way of specifying a colour in CSS is to use hexadecimal notation: an octothorpe (#) followed by six digits. You can also use keywords and RBG notation, but I always use hexadecimal. One great shortcut that many don’t know about is that when a colour consists of three pairs of hexadecimal digits, you can omit one digit from each pair:

#000000 becomes #000, #336699 becomes #369.

Box dimensions

The properties that affect box dimensions share the same syntax: the shorthand property followed by one to four space separated values:

  • property:value1;

  • property:value1 value2;

  • property:value1 value2 value3;

  • property:value1 value2 value3 value4;

Which sides of the box the values affect depends on how many values you specify. Here’s how it works:

  • One value: all sides

  • Two values: top and bottom, right and left

  • Three values: top, right and left, bottom

  • Four values: top, right, bottom, left

Thinking of the face of a clock is an easy way of remembering which side each value affects. Start at 12 o’clock (top), then 3 (right), 6 (bottom), and 9 (left). You can also think of the TRouBLe you’ll be in if you don’t remember the correct order – I first saw this in Eric Meyer’s excellent book Eric Meyer on CSS.

Margin and padding

Using shorthand for these properties can save a lot of space. For example, to specify different margins for all sides of a box, you could use this:

  1. margin-top:1em;

  2. margin-right:0;

  3. margin-bottom:2em;

  4. margin-left:0.5em;

But this is much more efficient:

  1. margin:1em 0 2em 0.5em;

The same syntax is used for the padding property.

Borders

Borders are slightly more complicated since they can also have a style and a colour. To give an element a one pixel solid black border on all sides, you could use the following CSS:

  1. border-width:1px;

  2. border-style:solid;

  3. border-color:#000;

A more compact way would be to use the border shorthand:

  1. border:1px solid #000;

I always specify border values in that order:

  1. border:width style color;

Most browsers don’t care about the order, and according to the specification they shouldn’t, but I don’t see a reason for not using the same order as the W3C does in the specification. There’s always the chance of a browser being very strict about the order of shorthand values.

The same syntax can be used with the border-top, border-right, border-bottom, and border-left shorthand properties to define the border of any single side of a box.

You don’t have to specify all three values. Any omitted values are set to their initial values. The initial values are medium for width, none for style, and the value of the element’s color property for color.

How wide a medium border is depends on the user agent.

Note that since the initial value for style is none you do need to specify a style if you want the border to be visible.

The border-width, border-style, and border-color properties used in the first border example above are themselves shorthand properties. Their longhand alternatives are very rarely used, but they do exist:

  1. border-width:1px 2px 3px 4px;

is shorthand for

  1. border-top-width:1px;

  2. border-right-width:2px;

  3. border-bottom-width:3px;

  4. border-left-width:4px;

The border-style and border-color shorthands use the same syntax as border-width: the box dimensions syntax described above.

Using the various border shorthands can also save some typing when you want to give an element’s border different properties on different sides. These declarations will make an element’s right and bottom borders solid, black, and one pixel wide:

  1. border-right:1px solid #000;

  2. border-bottom:1px solid #000;

And so will these:

  1. border:1px solid #000;

  2. border-width:0 1px 1px 0;

First the borders on all sides are styled identically, and then the different widths are specified.

Backgrounds

Another very useful shorthand property is background. Instead of using background-color, background-image, background-repeat, background-attachment, and background-position to specify an element’s background, you can use just background:

  1. background-color:#f00;

  2. background-image:url(background.gif);

  3. background-repeat:no-repeat;

  4. background-attachment:fixed;

  5. background-position:0 0;

can be condensed to

  1. background:#f00 url(background.gif) no-repeat fixed 0 0;

Like with the border shorthands the order of the values isn’t supposed to matter, but I’ve seen reports of early versions of Safari having problems when the values aren’t listed in the order used in the W3C specification, which is this:

  1. background:color image repeat attachment position;

Remember that when you give two values for position, they have to appear together. When using length or percentage values, put the horizontal value first.

As with the border and border sides properties, you don’t have to specify all values. If a value is omitted, its initial value is used. The initial values for the individual background properties are as follows:

  • color: transparent

  • image: none

  • repeat: repeat

  • attachment: scroll

  • position: 0% 0%

This means that it’s pointless to use the background shorthand without giving a value for either color or image – doing so would make the background transparent.

I almost always use the background shorthand to specify background colours for elements, since background:#f00; is the same as background-color:#f00;.

Remember that this will remove any background image specified by a previous rule. Consider these rules:

  1. p {

  2. background:#f00 url(image.gif) no-repeat;

  3. }

  4. div p {

  5. background:#0f0;

  6. }

All paragraphs not in a div element will have a background image and be red where the image doesn’t cover the background. Any paragraph that is in a div will have a green background, and no background image.

Fonts

As with the background property, font can be used to combine several individual properties:

  1. font-style:italic;

  2. font-variant:small-caps;

  3. font-weight:bold;

  4. font-size:1em;

  5. line-height:140%;

  6. font-family:"Lucida Grande",sans-serif;

Can be combined into

  1. font:italic small-caps bold 1em/140% "Lucida Grande",sans-serif;

Again, when it comes to the order of the values, I see no reason not to use the order given by the W3C. Better safe than sorry.

When using the font shorthand you can omit any values except font-size and font-family – you always need to give values for those, and in that order. The initial values for the individual font properties are these:

  • font-style: normal

  • font-variant: normal

  • font-weight: normal

  • font-size: medium

  • line-height: normal

  • font-family: depends on the user agent

Lists

The shorthand property for ordered and unordered lists is list-style. I personally only use it to set the list-style-type property to none, which removes any bullets or numbering from the list:

  1. list-style:none;

instead of

  1. list-style-type:none;

You can also use it to set the list-style-position and list-style-image properties, so to specify that unordered lists should render their list item markers inside each list item, use an image for the list item markers, and use squares if that image is not available, the following two rules would do the same thing:

  1. list-style:square inside url(image.gif);

is shorthand for

  1. list-style-type:square;

  2. list-style-position:inside;

  3. list-style-image:url(image.gif);

Outlines

The outline property is very rarely used, mainly because of its current poor browser support – as far as I know only Safari, OmniWeb and Opera currently support it. Anyway, using the individual properties you can define an outline like this:

  1. outline-color:#f00;

  2. outline-style:solid;

  3. outline-width:2px;

or like this:

  1. outline:#f00 solid 2px;

Outlines have some interesting characteristics that make them useful: unlike borders, they do not take up any space and are always drawn on top of a box. This means that hiding or showing outlines doesn’t cause reflow, and they don’t influence the position or size of the element they are applied to or that of any other boxes. Outlines may also be non-rectangular.

Referred from : http://www.456bereastreet.com

Selector syntax

Posted on April 15, 2009 - 12:44 pm by

A simple selector is either a type selector or universal selector followed immediately by zero or more attribute selectors, ID selectors, or pseudo-classes, in any order. The simple selector matches if all of its components match.

A selector is a chain of one or more simple selectors separated by combinators. Combinators are: whitespace, “>”, and “+”. Whitespace may appear between a combinator and the simple selectors around it.

The elements of the document tree that match a selector are called subjects of the selector. A selector consisting of a single simple selector matches any element satisfying its requirements. Prepending a simple selector and combinator to a chain imposes additional matching constraints, so the subjects of a selector are always a subset of the elements matching the rightmost simple selector.

One pseudo-element may be appended to the last simple selector in a chain, in which case the style information applies to a subpart of each subject.

The Complete CSS Tags

Posted on February 6, 2009 - 8:20 am by

Text and Fonts

font

Colours and Backgrounds

The Box Model – dimensions, padding, margin and borders

Positioning and Display

Lists

Tables

Generated Content

Paged Media

Misc.

The Whole Shebang

Rounded Corners

Posted on January 15, 2009 - 1:07 pm by

When New WordPress started using this i though you know Internet Explorer is definitely out now when i’m doing some css work that needs rounded corners I’m mostly using only this technique because buyers are ok with it although it’s just for FireFox and Safari. And since most of people still don’t know about this i figured it’s good thing to share.

Of course i’m talking about Border-radius property for FireFox and Safari 3 (only). And here are some nice examples how to use it.

#box { background: #eee; border: 1px solid #ccc; padding: 15px; -moz-border-radius: 10px; -webkit-border-radius: 10px; }

And of course you don’t have to make all corners rounded, it can be just top left etc, so the code goes like this (small not, for example you can’t make rounded corners on images and stuff like that)

* -moz-border-radius-topleft and -webkit-border-top-left-radius
* -moz-border-radius-topright and -webkit-border-top-right-radius
* -moz-border-radius-bottomleft and -webkit-border-bottom-left-radius
* -moz-border-radius-bottomright and -webkit-border-bottom-right-radius

100% height model css?

Posted on July 28, 2008 - 6:29 am by

I had been looking around for a way to accomplish fixed header and footer on a website when scrolling, and somehow i haven’t got it right with background attachment: fixed, neither i got it with absolute position…

I have a main Div called wrapper, inside there are three main Divs: header, content and footer, and each one of them has sub Divs inside for the content of each one. So the structure goes something like this in general terms:

body[

[ Div:wrapper
Div:Header
Div:top-banner
Div:Menu
Div:Buttons
]
[Div:Content]

[Div:Footer
Div:bottom-banner
]
]

is there any way to accomplish that the header and footer remain “locked” at the top and bottom of the browser window and only the content scrolls down.

See Here is the proper solution:

html, body {
height: 100%;
}

body {
any other styles;
}

#container {
min-height: 100%;
other styles;
}
* html #container {height: 100%;}/*IE6*/

this way, your page start out 100% but can grow bigger as content demands.

CSS font shorthand rule

Posted on June 15, 2008 - 12:54 pm by

When styling fonts with CSS you may be doing this:
font-size: 1em;
line-height: 1.5em;
font-weight: bold;
font-style: italic;
font-variant: small-caps;
font-family: verdana,serif;

There’s no need though as you can use this CSS shorthand property:
font: 1em/1.5em bold italic small-caps verdana,serif

Much better! Just a couple of words of warning: This CSS shorthand version will only work if you’re specifying both the font-size and the font-family. Also, if you don’t specify the font-weight, font-style, or font-varient then these values will automatically default to a value of normal, so do bear this in mind too.

Why tables for layout is stupid:

Posted on June 6, 2008 - 6:44 am by

Tables existed in HTML for one reason: To display tabular data. But then border=”0″ made it possible for designers to have a grid upon which to lay out images and text. Still the most dominant means of designing visually rich Web sites, the use of tables is now actually interfering with building a better, more accessible, flexible, and functional Web. Find out where the problems stem from, and learn solutions to create transitional or completely table-less layout.

The problem with using tables:

  • mixes presentational data in with your content.
    • This makes the file sizes of your pages unnecessarily large, as users must download this presentational data for each page they visit.
    • Bandwidth ain’t free.
  • This makes redesigns of existing sites and content extremely labor intensive (and expensive).
  • It also makes it extremely hard (and expensive) to maintain visual consistency throughout a site.
  • Table-based pages are also much less accessible to users with disabilities and viewers using cell phones and PDAs to access the Web.

Modern browsers are much better at rendering Web standards and we don’t need to use these archaic methods any more.

Instead of nesting tables within tables and filling empty cells with spacer GIFs, we can use much simpler markup and CSS to lay out beautiful sites that are faster to load, easier to redesign, and more accessible to everyone.

By using structural markup in our HTML documents and Cascading Style Sheets to lay out our pages, we can keep the actual content of our pages separated from the way they are presented.

This has several advantages over using tables….

Redesigns are easier and less expensive

By removing presentational markup from your pages, redesigns of existing sites and content is much less labor intensive (and much less expensive). To change the layout of the site, all you need to do is change the style sheets; you do not need to edit the pages themselves at all.

Using Web standards reduces the file sizes of your pages, as users no longer need to download presentational data with each page they visit. The Style sheets that control layout are cached by viewers’ browsers.

Reduced file size means faster loads and lower hosting costs.

Using Web standards also makes it extremely easy to maintain visual consistency throughout a site. Since pages use the same CSS document for their layout, they are all formatted the same.

This strengthens your brand and makes your site more usable.

Using Web standards makes our pages much more accessible to users with disabilities and to viewers using mobile phones and PDAs to access the Web.

Visitors using screen readers (as well as those with slow connections) do not have to wade through countless table cells and spacers to get at the actual content of our pages.

In other words, separating content from the way it is presented makes your content device-independent.

Speaking of accessiblity, minimizing your markup and using header tags properly will also help improve your search engine ranking.

Reducing the ratio of code to content, using keywords in your header tags, and replacing header GIFs with actual text will all help your sites get better search engine results.

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