getDescendantsByClassName

getDescendantsByClassName.js

/**
* This is effectively an implementation of 
* `element.getElementsByClassName`
* (see: https://developer.mozilla.org/en-US/docs/Web/API/Element.getElementsByClassName)
*
* You should probably just use the built-in method.
* 
* This is therefore a partial replacement for the jQuery find() method
* in pure JavaScript.
* 
* It extends this JSFiddle: http://jsfiddle.net/franverona/8Tx27/1/
* From this StackOverflow answer: http://stackoverflow.com/a/10381659/613540
*/

/**
 * Get descendants of parent by class name
 */
function getDescendantsByClassName(parent, searchClass) {
    var matches = [];

    // Iterate over children
    for (var childIndex = 0; childIndex < parent.children.length; childIndex++) {
        var child = parent.children[childIndex];

        classString = child.className || '';

        var classes = classString.split(" ");

        // Iterate over classes
        for (var classIndex = 0; classIndex < classes.length; classIndex++) {
            var childClass = classes[classIndex]

            if (childClass == searchClass) {
                // Save any children that have a matching class
                matches.push(child);
            }
        }

        // Add any matching child nodes of this node
        childDescentants = getDescendantsByClass(child, searchClass);

        matches = matches.concat(childDescentants);
    }
    return matches;
}