CSS 笔记六(Image/Attribute Selectors)

Image Opacity / Transparency

  • The CSS opacity property is a part of the CSS3 recommendation.

Example

 img {
opacity: 0.4;
filter: alpha(opacity=40); /* For IE8 and earlier */
} img:hover {
opacity: 1.0;
filter: alpha(opacity=100); /* For IE8 and earlier */
}

Image Sprites

  • An image sprite is a collection of images put into a single image.

Example

CSS 笔记六(Image/Attribute Selectors)

 <!DOCTYPE html>
<html>
<head>
<style>
#navlist {
position: relative;
} #navlist li {
margin: 0;
padding: 0;
list-style: none;
position: absolute;
top: 0;
} #navlist li, #navlist a {
height: 44px;
display: block;
} #home {
left: 0px;
width: 46px;
background: url('img_navsprites_hover.gif') 0 0;
} #prev {
left: 63px;
width: 43px;
background: url('img_navsprites_hover.gif') -47px 0;
} #next {
left: 129px;
width: 43px;
background: url('img_navsprites_hover.gif') -91px 0;
} #home a:hover {
background: url('img_navsprites_hover.gif') 0 -45px;
} #prev a:hover {
background: url('img_navsprites_hover.gif') -47px -45px;
} #next a:hover {
background: url('img_navsprites_hover.gif') -91px -45px;
}
</style>
</head>
<body> <ul id="navlist">
<li id="home"><a href="default.asp"></a></li>
<li id="prev"><a href="css_intro.asp"></a></li>
<li id="next"><a href="css_syntax.asp"></a></li>
</ul> </body>
</html>

CSS Attribute Selectors

  • Style HTML elements that have specific attributes or attribute values.

1> CSS [attribute] Selector

  • Used to select elements with a specified attribute.

2> CSS [attribute="value"] Selector

  • Used to select elements with a specified attribute and value.

Example

 a[target] {
background-color: yellow;
}
a[target="_blank"] {
background-color: blue;
}

3> CSS [attribute~="value"] Selector

  • Used to select elements with an attribute value containing a specified word.

4> CSS [attribute*="value"] Selector

  • Used to select elements whose attribute value contains a specified value.
 [title~=flower] {
border: 5px solid yellow;
}
title="klematis flower" > yes
title="flower" > yes
title="tree_flower" > no [class*="te"] {
background: yellow;
}
class="first_test" > yes
class="mytest" > yes

5> CSS [attribute|="value"] Selector

  • Used to select elements with the specified attribute starting with the specified value.

6> CSS [attribute^="value"] Selector

  • Used to select elements whose attribute value begins with a specified value.
 [class|=top] {
background: yellow;
}
class="top-header" > yes
class="top-text" > yes
class="topcontent" > no [class^="top"] {
background: yellow;
</style>
class="top-header" > yes
class="top-text" > yes
class="topcontent" > yes

7> CSS [attribute$="value"] Selector

  • Used to select elements whose attribute value ends with a specified value.
 [class$="test"] {
background: yellow;
}
class="first_test" > yes
class="my-test" > yes
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