Question

Trying to create a navigation from an existing menu, here’s the markup:

<nav>
    <ul id="nav">
        <li>
            <a href="?=home">Home</a>
            <ul>
                <li><a href="?=sub-1">Sub 1</a></li>
                <li><a href="?=sub-2">Sub 2</a></li>
                <li><a href="?=sub-3">Sub 3</a></li>
                <li><a href="?=sub-4">Sub 4</a></li>
                <li><a href="?=sub-5">Sub 5</a></li>
            </ul>
        </li>
        <li>
            <a href="?=about">About</a>
        </li>
        <li>
            <a href="?=services">Services</a>
        </li>
        <li>
            <a href="?=portfolio">Portfolio</a>
        </li>
        <li>
            <a href="?=contact">Contact</a>
        </li>
    </ul>
</nav>

This is the javascript loop I have, which currently finds and appends each top level menu item, but I really am unsure how to target the nested children and append them with a hyphen for nested elements.

var nav = document.getElementById('nav');
    var list = nav.children.length;

    for (var i = 0; i < list; i++) {
        var option = document.createElement('option');
        option.innerHTML = nav.children[i].children[0].innerHTML;
        option.value = nav.children[i].children[0].href;
        select.appendChild(option);
    }

So it would basically do this:

<select>
    <option value="?=home">Home</option>
    <option value="?=sub-1">- Sub 1</option>
    <option value="?=sub-2">- Sub 2</option>

Etc. etc…

Any help would be massively appreciated! Thank you.

Answer 1

You can traverse your ul recursively. That will handle multilevel menus as well. Keep track of the recursion level and the higher level items to concatenate with the dashes.

A description of the approach: http://blog.swapnilsarwe.com/javascript-traversing-html-dom-recursively.html

---

Edit: Here’s an example. You’ll also need to put an HTML select element with id=’select’ somewhere:

buildSelect(document.getElementById('nav'), '', document.getElementById('select'));

function buildSelect(current, optionSoFar, select) {
    var currentLevelOption = optionSoFar;
    for (var i=0; i<current.children.length; i++) {
        var child = current.children[i];
        if ('A' == child.tagName) {
            var currentLevelLabel = child.innerText;
            var separator = ('' == optionSoFar) ? '' : ' - ';
            currentLevelOption = optionSoFar + separator + currentLevelLabel;
            var option = document.createElement('option');
            option.innerText = currentLevelOption;
            option.value = child.href;
            select.appendChild(option);
        }
        else {
            buildSelect(child, currentLevelOption, select);
        }
    }
}

​
​
Here’s a fiddle: http://jsfiddle.net/GM54F/3/