Detailed graphic explanation of the differences between rgba, rgb and opacity in CSS-CSS Tutorial-php.cn

Detailed graphic explanation of the differences between rgba, rgb and opacity in CSS

yulia

Release： 2018-10-22 15:19:38

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There are many ways to set background color in CSS, such as background-color, rgb, rgba, etc. Do you know the difference between rgba, rgb and opacity? This article will tell you about the differences between rgba, rgb and opacity. It has certain reference value. Interested friends can refer to it.

The difference between rgb and rgba:

rgb refers to red, green, and blue. The value is between 0 and 255. For example: black can Represented as rgb(0,0,0)

rgba refers to red (red), green (green), blue (blue), transparency (opacity), and the value of transparency is between 0 and 1

The difference between rgba and rgb is that rgba can set the transparency of the background color, but rgb cannot

Example 1: Use background: rgb(255,0,0) to set the background color to red

<!DOCTYPE html>
<html>
 <head>
  <meta charset="UTF-8">
  <title></title>
  <style type="text/css">
   .a1{
    width: 300px;
    height: 200px;
    position: relative;
    border: 1px solid black;
   }
   .a2{
    width: 200px;
    height: 100px;
    position: absolute;
    top: 50px;
    left: 50px;
    background: rgb(255,0,0);
   }
  </style>
 </head>
 <body>
  <div class="a1"></div>
  <div class="a2"></div>
 </body>
</html>

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Rendering:

Detailed graphic explanation of the differences between rgba, rgb and opacity in CSS

Example 2: Use background: rgba(255,0,0,0.5) to set the background color to translucent red

 .a1{
    width: 300px;
    height: 200px;
    position: relative;
    border: 1px solid black;
   }
   .a2{
    width: 200px;
    height: 100px;
    position: absolute;
    top: 50px;
    left: 50px;
    background: rgba(255,0,0,0.5);
   }

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Rendering:

Detailed graphic explanation of the differences between rgba, rgb and opacity in CSS

##The difference between rgba() and opacity:

Both can set the transparency effect, but the opacity attribute will act on For elements and all elements inside the element, such as sub-elements, rgba will only act on itself and not on sub-elements. Please compare the renderings for the specific differences.

Example 3: Use opacity: 0.5 to set transparency, the code is as follows:

<style type="text/css">
   .a1{
    width: 300px;
    height: 200px;
    position: relative;
    border: 1px solid black;
   }
   .a2{
    width: 200px;
    height: 100px;
    position: absolute;
    top: 50px;
    left: 50px;
    background: red;
    opacity: 0.5;
   }
</style>
<body>
  <div class="a1"></div>
  <div class="a2">我是盒子里面的内容，文字不需要透明</div>
</body>

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Rendering:

Detailed graphic explanation of the differences between rgba, rgb and opacity in CSS
From the rendering You can see the difference between rgba, rgb and opacity. rgb can only set the background color; rgba can set transparency, and the transparency will not act on the elements inside. opacity can set transparency, but the transparency will act on the elements inside. superior.

The above combined with examples introduces you to the differences between rgba, rgb and opacity. Beginners can try it themselves and deepen their impression. I hope this article will be helpful to you!

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