Why CSS abbreviations?
When designing WEB standard web pages, it is essential to write a large amount of CSS syntax. Generally, we can automatically generate the corresponding CSS code through the "CSS Style" panel of the Dreamweaver software.
However, although the CSS code generated by the software is clear and easy to understand, it is because of CSS’s clear explanation of the bar style definition that it makes reading the CSS code appear lengthy and complicated. At the same time, the number of bytes of the CSS code is also Increase... This is difficult to tolerate for people who pursue high efficiency and perfection.
For example, when we define the padding size for an element, we use padding. When there are different requirements for top, right, bottom, and left padding, the code generated by the software may be like this:
.t1 {
padding-top: 3px;
padding-right: 20px;
padding-bottom: 3px;
padding-left: 20px;
}
To simply write it, it would be
.t2 {
padding: 3px 20px 3px 20px;
}
The four side values of padding correspond to top (upper), right (right), and bottom (lower). , left (left). Of course, this example can also be abbreviated as:
.t3 {
padding: 3px 20px 3px;
}
When there is no left, the default value is the value of right. When there is no bottom, the default value is the value of top, so the simplest one in this example is :
.t4{
padding: 3px 20px;
}
(Of course, if padding has only one value, it means that the top, right, bottom and left are the same.)
The lengthy 4 lines of code in the above example are condensed into one line of introduction code - this That’s the advantage of CSS abbreviations.
Of course, many times when we learn other people’s CSS experience, we will also see many similar CSS abbreviations. But if you don’t understand it yourself, you won’t understand how to learn these CSS methods and experience. Therefore, we must understand and master some commonly used CSS abbreviation syntax.
Commonly used CSS abbreviation syntax
1, Backgrounds
The attributes of the background are as follows:
background-color: #FFCCFF;
background-image: url(/images/2007-6 .jpg);
background-repeat: no-repeat;
background-attachment: fixed;
background-position: center bottom;
The CSS code can be abbreviated as:
background:#FCF url (/images/2007-6.jpg) no-repeat fixed center bottom;
Background: background color, background image, background repeat, background attachment, background horizontal position, background vertical Position
The background color "#FFCCFF" can also be abbreviated as "#FCF", which is for the hexadecimal color value. If the value of each two digits (RRGGBB) is the same, it can be abbreviated to half (RGB) . At the same time, the background image does not need to be enclosed in double quotes.