YouTipMet Element Issamenode
## XML DOM: isSameNode() Method
The `isSameNode()` method is a standard XML DOM method used to determine whether a specified node is the exact same node as an existing node.
This method is highly useful when you need to verify identity rather than equality. It checks if two references point to the exact same object in memory, rather than just checking if they have the same tag name, attributes, or child values.
---
## Definition and Usage
* The `isSameNode()` method compares two nodes to see if they are the **same node**.
* It returns `true` if the two nodes are identical (i.e., they reference the exact same object in the DOM tree).
* It returns `false` if the nodes are different, even if they have the same node type, tag name, attributes, and child nodes.
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## Syntax
```javascript
elementNode.isSameNode(node)
```
### Parameters
| Parameter | Type | Required / Optional | Description |
| :--- | :--- | :--- | :--- |
| `node` | Node Object | **Required** | The node object you want to compare with the current `elementNode`. |
### Return Value
| Return Type | Description |
| :--- | :--- |
| `Boolean` | Returns `true` if the nodes are the same node; otherwise, it returns `false`. |
---
## Code Example
The following code snippet loads the XML file [books.xml](/try/demo_source/books.xml) using `loadXMLDoc()` and checks whether two retrieved nodes are the same node.
```javascript
// Load the XML document
xmlDoc = loadXMLDoc("books.xml");
// Retrieve the first and second elements
var x = xmlDoc.getElementsByTagName("book");
var y = xmlDoc.getElementsByTagName("book");
// Check if they are the same node
var result = x.isSameNode(y);
document.write(result);
```
### Output
```text
false
```
---
## Important Considerations
### 1. Identity vs. Equality (`isSameNode()` vs. `isEqualNode()`)
It is crucial to distinguish between `isSameNode()` and `isEqualNode()`:
* **`isSameNode(node)`**: Checks if two references point to the **exact same node object** in the DOM.
* **`isEqualNode(node)`**: Checks if two nodes are **equal** in terms of structure and content (i.e., they have the same node type, attributes, tag name, and child nodes), even if they are different objects in memory.
### 2. Modern JavaScript / Web API Note
In modern web browsers (HTML5 DOM4 specification), the `isSameNode()` method has been deprecated because you can simply use the strict equality operator (`===`) to achieve the exact same result.
For example:
```javascript
// Modern equivalent of x.isSameNode(y)
if (x === y) {
// They are the same node
}
```
However, `isSameNode()` remains a part of the XML DOM legacy specifications and is still supported in many XML parsing environments.