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:
view sourceprint?

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:
view sourceprint?

1.

findNodeByTag(myDOMobj,

"img"

);