San Francisco Bay Area Professional Blog: Traverse/walk DOM tree recursively

San Francisco Bay Area Professional Blog: Traverse/walk DOM tree recursively

Traverse/walk DOM tree recursively

Task definition: You have a DOM tree (startNode which can be the whole document), and need to find first specific tag in this tree.

Here is the recursion function to do this:

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1.function findNodeByTag(startNode, tagName) {

2.    if (startNode.nodeName.toLowerCase() == tagName.toLowerCase()) return startNode;

3.    var childList = startNode.childNodes;

4.    for (var i=0; i<childList.length; i++) {

5.        return findNodeByTag(childList[i], tagName);

6.    }

7.    return null;

8.}

And you call it:

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1.findNodeByTag(myDOMobj, "img");