HTML Style backgroundPosition用法及代碼示例

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

用法:

獲取backgroundPosition屬性
```
object.style.backgroundPosition
```
設置backgroundPosition屬性
```
object.style.backgroundPosition = value
```

屬性值：

keyword values:用於通過關鍵字指定位置。如果僅指定一個值，則默認情況下另一個值為“ center”。可能的關鍵字組合為：
- top left
- top center
- top right
- center left
- center center
- center right
- bottom left
- bottom center
- bottom right
x％y％：用於使用百分比指定排名。 x％確定水平位置，y％確定相對於初始左上位置的垂直位置。
xpos ypos：使用像素或任何其他CSS測量來指定位置。 xpos確定水平位置，ypos確定相對於初始左上位置的垂直位置。
initial：this用於將此屬性設置為其默認值。
inherit：this從其父級繼承屬性。

使用以下示例解釋這些值：

示例1：使用關鍵字值。在此示例中，我們使用值“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>

輸出：

按下按鈕之前：
按下按鈕後：

示例2：使用百分比指定排名。我們使用“ 25％75％”定位圖片。

<!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>

輸出：

按下按鈕之前：
按下按鈕後：

示例3：使用固定單位指定位置。我們使用“ 50px 25px”定位圖片。

<!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>

輸出：

按下按鈕之前：
按下按鈕後：

示例4：使用初始值。這會將位置設置為其默認值。

<!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>

輸出：

按下按鈕之前：
按下按鈕後：

示例5：使用繼承值。這將從其父元素繼承位置。

<!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>

輸出：

按下按鈕之前：
按下按鈕後：

支持的瀏覽器：backgroundPosition屬性支持的瀏覽器如下：

Chrome 1.0
Internet Explorer 4.0
Firefox 1.0
Opera 3.5
Safari 1.0

相關用法

注：本文由純淨天空篩選整理自sayantanm19大神的英文原創作品 HTML | DOM Style backgroundPosition Property。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。