HTML Style backgroundPosition用法及代码示例

HTML DOM样式backgroundPosition：设置或返回background-image在元素中的位置。

用法:

获取backgroundPosition属性
```
object.style.backgroundPosition
```
设置backgroundPosition属性
```
object.style.backgroundPosition = value
```

属性值：

keyword values:用于通过关键字指定位置。如果仅指定一个值，则默认情况下另一个值为“ center”。可能的关键字组合为：
- top left
- top center
- top right
- center left
- center center
- center right
- bottom left
- bottom center
- bottom right
x％y％：用于使用百分比指定排名。 x％确定水平位置，y％确定相对于初始左上位置的垂直位置。
xpos ypos：使用像素或任何其他CSS测量来指定位置。 xpos确定水平位置，ypos确定相对于初始左上位置的垂直位置。
initial：this用于将此属性设置为其默认值。
inherit：this从其父级继承属性。

使用以下示例解释这些值：

示例1：使用关键字值。在此示例中，我们使用值“右下”。

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <title> 
      DOM Style backgroundPosition Property 
    </title> 
    <style> 
        .bg-img { 
            height:300px; 
            width:300px; 
            border-style:solid; 
            background:  
url('https://media.geeksforgeeks.org/wp-content/uploads/sample_image.png') 
                        no-repeat center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color:green"> 
      GeeksforGeeks 
    </h1> 
    <b> 
      DOM Style backgroundPosition Property 
    </b> 
    <p> 
      Click on the button to change the  
      position of the background image 
    </p> 
    <div class="bg-img"> 
    </div> 
  
    <button onclick="changePos()"> 
        Change position of background image 
    </button> 
  
    <script> 
        function changePos() { 
            elem = document.querySelector('.bg-img'); 
  
            // Setting the position to bottom vertically 
            // and right horizontally 
            elem.style.backgroundPosition = 'bottom right'; 
        } 
    </script> 
</body> 
  
</html>

输出：

按下按钮之前：
按下按钮后：

示例2：使用百分比指定排名。我们使用“ 25％75％”定位图片。

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <meta charset="UTF-8"> 
    <title> 
      DOM Style backgroundPosition Property 
    </title> 
    <style> 
        .bg-img { 
            height:300px; 
            width:300px; 
            border-style:solid; 
            background:  
url('https://media.geeksforgeeks.org/wp-content/uploads/sample_image.png')  
                        no-repeat center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color:green"> 
      GeeksforGeeks 
    </h1> 
    <b> 
      DOM Style backgroundPosition Property 
    </b> 
    <p> 
      Click on the button to change the 
      position of the background image 
    </p> 
  
    <div class="bg-img"> 
    </div> 
    <button onclick="changePos()"> 
        Change position of background image 
    </button> 
  
    <script> 
        function changePos() { 
            elem = document.querySelector('.bg-img'); 
  
            // Setting the position to 25% horizontally 
            //and 75% vertically 
            elem.style.backgroundPosition = '25% 75%'; 
        } 
    </script> 
</body> 
  
</html>

输出：

按下按钮之前：
按下按钮后：

示例3：使用固定单位指定位置。我们使用“ 50px 25px”定位图片。

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <title> 
      DOM Style backgroundPosition Property 
    </title> 
    <style> 
        .bg-img { 
            height:300px; 
            width:300px; 
            border-style:solid; 
            background:  
url('https://media.geeksforgeeks.org/wp-content/uploads/sample_image.png') 
                        no-repeat center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color:green"> 
      GeeksforGeeks 
    </h1> 
    <b> 
      DOM Style backgroundPosition Property 
    </b> 
    <p> 
      Click on the button to change the  
      position of the background image</p> 
    <div class="bg-img"> 
    </div> 
  
    <button onclick="changePos()"> 
        Change position of background image 
    </button> 
  
    <script> 
        function changePos() { 
            elem = document.querySelector('.bg-img'); 
  
            // Setting the position to 50px horizontally 
           //and 25px horizontally 
            elem.style.backgroundPosition = '50px 25px'; 
        } 
    </script> 
</body> 
  
</html>

输出：

按下按钮之前：
按下按钮后：

示例4：使用初始值。这会将位置设置为其默认值。

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <title>DOM Style backgroundPosition Property</title> 
    <style> 
        .bg-img { 
            height:300px; 
            width:300px; 
            border-style:solid; 
            background:  
url('https://media.geeksforgeeks.org/wp-content/uploads/sample_image.png')  
                        no-repeat center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color:green"> 
      GeeksforGeeks 
    </h1> 
    <b> 
      DOM Style backgroundPosition Property 
    </b> 
    <p> 
      Click on the button to change the  
      position of the background image 
    </p> 
    <div class="bg-img"> 
    </div> 
  
    <button onclick="changePos()"> 
        Change position of background image 
    </button> 
  
    <script> 
        function changePos() { 
            elem = document.querySelector('.bg-img'); 
  
            // Setting the position to the default  
            // value with initial 
            elem.style.backgroundPosition = 'initial'; 
        } 
    </script> 
</body> 
  
</html>

输出：

按下按钮之前：
按下按钮后：

示例5：使用继承值。这将从其父元素继承位置。

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <title> 
      DOM Style backgroundPosition Property 
    </title> 
    <style> 
        /* Parent element */ 
          
        #parent { 
            height:300px; 
            width:300px; 
            border-style:solid; 
            /* Setting the parent's background-position 
          //to center left*/ 
            background-position:center left; 
        } 
          
        .bg-img { 
            height:300px; 
            width:300px; 
            background:  
url('https://media.geeksforgeeks.org/wp-content/uploads/sample_image.png') 
                        no-repeat center; 
        } 
    </style> 
</head> 
  
<body> 
    <h1 style="color:green"> 
      GeeksforGeeks 
    </h1> 
    <b> 
      DOM Style backgroundPosition Property 
    </b> 
    <p> 
      Click on the button to change the  
      position of the background image 
    </p> 
    <div id="parent"> 
        <div class="bg-img"></div> 
    </div> 
  
    <button onclick="changePos()"> 
        Change position of background image 
    </button> 
  
    <script> 
        function changePos() { 
            elem = document.querySelector('.bg-img'); 
  
            // Setting the position to inherit from its parent 
            elem.style.backgroundPosition = 'inherit'; 
        } 
    </script> 
</body> 
  
</html>

输出：

按下按钮之前：
按下按钮后：

支持的浏览器：backgroundPosition属性支持的浏览器如下：

Chrome 1.0
Internet Explorer 4.0
Firefox 1.0
Opera 3.5
Safari 1.0

相关用法

注：本文由纯净天空筛选整理自sayantanm19大神的英文原创作品 HTML | DOM Style backgroundPosition Property。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。