jquery - Javascript - Recursive function to iterate through elements

Question

I've just started reading up on JavaScript and I'm trying to write a small recursive function that would search through given nodes and return a list of values as a string.

My HTML structure could be something like

<div id="parentfolder">parentfolder1
    <div class ="item1">item1</div>
    <div class ="item2">item2</div>
    <div id="parentfolder">parentfolder2
        <div class ="item1">item1</div>
        <div class ="item2">item2</div>
    </div>
</div>

And Here is my Javascript function:

function jsoncreator(parentfolderclass){
    var jstring = '';

    //get first occurance of parent folder
    var parentfolder = document.getElementById(parentfolderclass);
    var childnodes = parentfolder.childNodes;

    for (property in childnodes){
        jstring += property+ childnodes[property];
        if(childnodes[property] === parentfolderclass){
            jsoncreator(parentfolderclass);
            jstring += childnodes[property].value + '<br>';
        }
        else{
            //jstring += childnodes[i].value + '<br>';
        }
    }
    document.write(jstring);
}

All im getting back is

0[object Text]1[object HTMLDivElement]2[object Text]3[object HTMLDivElement]4[object Text]5[object HTMLDivElement]6[object Text]length7itemfunction item() { [native code] }

When I try to print the childnodes values, I get a bunch of undefined returns.

If anybody could explain what I'm doing wrong, I'd really appreciate it.

Answer 1

You will need to do something like the following (recursive cross-browser)

Javascript

function walkTheDOM(node, func) {
    func(node);
    node = node.firstChild;
    while (node) {
        walkTheDOM(node, func);
        node = node.nextSibling;
    }
}

function textNodeValuesToArray(node) {
    if (typeof node === "string") {
        node = document.getElementById(node);
    }

    var arrayOfText = [];

    function pushText(currentNode) {
        if (currentNode.nodeType === 3) {
            arrayOfText.push(currentNode.nodeValue);
        }
    }

    walkTheDOM(node, pushText);

    return arrayOfText;
}

console.log(textNodeValuesToArray("parentfolder"));

On jsfiddle

Or using treewalker

Browser compatibility

Supported by IE9+, FF2+, Chrome 1+, Safari 3+, Opera 9+

Javascript

function textNodeValuesToArray(node) {
    if (typeof node === "string") {
        node = document.getElementById(node);
    }

    var arrayOfText = [],
        treeWalker = document.createTreeWalker(node, NodeFilter.SHOW_TEXT, {
            acceptNode: function (node) {
                return NodeFilter.FILTER_ACCEPT;
            }
        }, false);

    while (treeWalker.nextNode()) {
        arrayOfText.push(treeWalker.currentNode.nodeValue);
    }

    return arrayOfText;
}

console.log(textNodeValuesToArray("parentfolder"));

On jsfiddle

Without recursion and cross browser would be something like this

Javascript

Avoid using labels

Labels are not very commonly used in JavaScript since they make programs harder to read and understand. As much as possible, avoid using labels and, depending on the cases, prefer calling functions or throwing an error.

function walkDOM(root, func) {
    var node = root;

    start: while (node) {
        func(node);
        if (node.firstChild) {
            node = node.firstChild;
            continue start;
        }

        while (node) {
            if (node === root) {
                break start;
            }

            if (node.nextSibling) {
                node = node.nextSibling;
                continue start;
            }

            node = node.parentNode;
        }
    }
}

function textNodeValuesToArray(node) {
    if (typeof node === "string") {
        node = document.getElementById(node);
    }

    var arrayOfText = [];

    function pushText(currentNode) {
        if (currentNode.nodeType === 3) {
            arrayOfText.push(currentNode.nodeValue);
        }
    }

    walkDOM(node, pushText);

    return arrayOfText;
}

console.log(textNodeValuesToArray("parentfolder"));

On jsfiddle