XML DOM previousSibling Property
Element Object
Example
The following code fragment loads "books.xml" into xmlDoc and gets the previous sibling node from the first <author> element:
xhttp.onreadystatechange = function() {
if (xhttp.readyState == 4 && xhttp.status == 200) {
myFunction(xhttp);
}
};
xhttp.open("GET", "books.xml", true);
xhttp.send();
// Check if the previous sibling node is an element node
function get_previoussibling(n) {
var x = n.previousSibling;
while (x.nodeType != 1) {
x = x.previousSibling;
}
return x;
}
function myFunction(xml) {
var xmlDoc = xml.responseXML;
var x = xmlDoc.getElementsByTagName("author")[0];
var y = get_previoussibling(x);
document.getElementById("demo").innerHTML = x.nodeName + " = " +
x.childNodes[0].nodeValue +
"<br>Previous sibling: " + y.nodeName + " = " +
y.childNodes[0].nodeValue;
}
The output of the code above will be:
Previous sibling: title = Everyday Italian
Definition and Usage
The previousSibling property returns the previous sibling node (the previous node in the same tree level) of the selected element
If there is no such node, this property returns null.
Syntax
Tips and Notes
Note: Firefox, and most other browsers, will treat empty white-spaces or new lines as text nodes, Internet Explorer will not. So, in the example below, we have a function that checks the node type of the previous sibling node.
Element nodes has a nodeType of 1, so if the previous sibling node is not an element node, it moves to the previous node, and checks if this node is an element node. This continues until the previous sibling node (which must be an element node) is found. This way, the result will be correct in all browsers.
Tip: To read more about the differences between browsers, visit our DOM Browsers chapter in our XML DOM Tutorial.
Try-It-Yourself Demos
nextSibling - Get the next sibling of a node
Element Object
