How to correctly use innerHTML to create an element (with possible children) from a html string?

Question

Note: I do NOT want to use any framework.

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The goal is just to create a function that will return an element based on an HTML string.

Answer 1

This is similar to the answer from palswim, except that it doesn't bother with creating a clone, and uses a while() loop instead, always appending the node at [0].

function createElement( str ) {
    var frag = document.createDocumentFragment();

    var elem = document.createElement('div');
    elem.innerHTML = str;

    while (elem.childNodes[0]) {
        frag.appendChild(elem.childNodes[0]);
    }
    return frag;
}

Answer 2

You'd have to attach the new element somewhere. Try using a DocumentFragment object in conjunction with the div you created:

function createElement(str) {
    var div = document.createElement('div');
    div.innerHTML = str;
    var container = document.createDocumentFragment();
    for (var i=0; i < div.childNodes.length; i++) {
        var node = div.childNodes[i].cloneNode(true);
        container.appendChild(node);
    }
    return container.childNodes;
}

It's more overhead, but it does what you want. Note that DOM elements' .insertAdjacentHTML member function is coming in HTML5.

For that complex string you passed, it isn't valid XHTML syntax - you can't have a block element as a child of <p> (<h2> is a block level element).