Setting method: 1. Use the RGBA() function, the syntax "Attribute: RGBA (red value, green value, blue value, transparency value);"; 2. Use the opacity attribute, the syntax "opacity: transparency value;". The transparency value can be set from 0.0 (fully transparent) to 1.0 (fully opaque).
The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.
#How to set opacity in html?
Method 1
rgba() sets color transparency
Syntax:
rgba（R,G,B,A）;
RGBA is the abbreviation for the three words Red (red) Green (green) Blue (blue) and Alpha (opacity). RGBA color values are an extension of RGB color values with an alpha channel - which specifies the opacity of the object.
Introduction to the values in rgba():
R: red value. Positive integer (0~255)
G: green value. Positive integer (0~255)
B: Blue value. Positive integer (0~255)
A: Transparency. The value is between 0 and 1.
rgba() can simply set the color transparency, which has many applications in page layout. For example: make the background transparent, but the text above is opaque.
Code example:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>rgba()</title>
<style>
.demo{
width: 350px;
height: 300px;
margin: 50px auto;
}
.demo *{
width: 120px;
height: 120px;
margin: 10px;
float: left;
}
.demo1{
background:rgba(255,0,0,1);
}
.demo2{
background:rgba(255,0,0,0.5);
}
</style>
</head>
<body>
<div class="demo">
<div class="demo1">背景色不透明，文字不透明！</div>
<div class="demo2">背景色半透明，文字不透明！</div>
</div>
</body>
</html>Rendering:
,
Method 2
opacity attribute setting background Transparency
Syntax:
opacity: value ;
value: Specify opacity, from 0.0 (fully transparent) to 1.0 (fully opaque).
opacityThe property is inherited and will make all elements in the container transparent;
Code example:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>opacity属性</title>
<style>
.demo{
width: 280px;
height: 140px;
margin: 50px auto;
}
.demo1,.demo2{
width: 120px;
height: 120px;
margin: 10px;
float: left;
background:#2DC4CB;
}
.demo1{
opacity:1;
}
.demo2{
opacity:0.5;
}
</style>
</head>
<body>
<div class="demo">
<div class="demo1">
<p>背景色不透明，文字不透明！</p>
</div>
<div class="demo2">
<p>背景色透明，文字也透明！</p>
</div>
</div>
</body>
</html>Rendering:
opacity:0.5; Makes all elements of the demo2 container appear translucent.
Summary: Although both the rgba() method and the opacity method can achieve transparency effects, rgba() only acts on the color of the element or its background color (the child element of the element with rgb() transparency set will not inherit its transparency effect); and opacity is inheritance, which not only affects the element itself, but also makes all sub-elements within the element transparent.
Recommended learning: HTML video tutorial
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