HTML DOM compareDocumentPosition() method Compare document locations-HTML Tutorial-php.cn

HTML DOM compareDocumentPosition() method Compare document locations

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Release： 2023-09-14 19:21:10

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HTML DOM The CompareDocumentPosition() method is used to compare the given node position with any other node in any document. The return type of this method is an integer type that describes their position in the document. The integer return value is as specified -

1: No relationship, the two nodes do not belong to the same document.
2: The first node (para1) is positioned after the second node (para2).
4: The first node (para1) is positioned before the second node (para2).
8: The first node (para1) is positioned inside the second node (para2).
16: The second node (para2) is positioned inside the first node (para1).
32: No relationship, or the two nodes are two attributes on the same element.

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Syntax

The following is the syntax of the HTML DOM CompareDocumentPosition() method-

node.compareDocumentPosition(node)

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The node here is the node object type, specifying that we want to compare with The node to which the current node is compared.

Example

Let us see an example of compareDocumentPosition() method -

<!DOCTYPE html>
<html>
<body>
<p id="para1">This is a paragraph</p>
<p id="para2">This is another paragraph</p>
<p>Click the button to compare the position of the two paragraphs.</p>
<button onclick="docPosition()">POSITION</button>
<p id="Sample"></p>
<script>
   function docPosition() {
      var p1 = document.getElementById("para1").lastChild;
      var p2 = document.getElementById("para2").lastChild;
      var x = p2.compareDocumentPosition(p1);
      document.getElementById("Sample").innerHTML = x;
   }
</script>
</body>
</html>

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Output

This will produce the following output-

HTML DOM compareDocumentPosition() 方法

比较文档位置

When clicking the "Position" button -

HTML DOM compareDocumentPosition() 方法

比较文档位置

In the above example -

we first create two The id is "para1" and the element of "

paragraph 2".

<p id="para1">This is a paragraph</p>
<p id="para2">This is another paragraph</p>

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Then we created a button POSTION that will execute the docPosition() method when the user clicks -

<button onclick="docPosition()">POSITION</button>

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The docPosition() method uses the getElementById() method on the document object to get< ;p> element. Then, it assigns the lastchild attribute values of the two paragraphs to variables p1 and p2 respectively.

Then, we call the compareDocumentPosition() method on p2 with p1 as a parameter. This means we want to compare the position of p2 relative to p1. Since here p2 is after p1, the return value is 2 -

function docPosition() {
   var p1 = document.getElementById("para1").lastChild;
   var p2 = document.getElementById("para2").lastChild;
   var x = p2.compareDocumentPosition(p1);
   document.getElementById("Sample").innerHTML = x;
}

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