javascript - contenteditable with nested span. Who has the focus?

Question

This question (to which I added a bounty) is related and gives the context and motivations (my GPLv3 MELT monitor on github; I added at last some README to it).

I am only interested in recent HTML5 compliant browsers (on GNU/Linux), e.g. Firefox 38 at least (and preferably 42) or Chrome 46 (on Debian/Sid desktop, x86-64)

So, suppose I have in my HTML5 page

<div id='myeditdiv' contenteditable='true'>
  <span class='foo_cl'>FOO<span class='bar_cl'>bar</span></span>
</div>

^{(actually the HTML is generated, and so is the DOM; I'm currently generating on the server side some javascript which constructs the DOM; of course I can change the generators!)}

And I am clicking so that the focus come between the two OO. How can I get the DOM element of foo_cl, preferably with Jquery.

Same question when focusing between ar. I want the bar_cl span.

Of course, $(':focus') don't work. It gives the div

FWIW, it is commit 9109ae5b3d168f1 of the MELT monitor.

PS. See my (november 26^th 2015) addenda to this question. Probably contenteditable is not useful to me, but tabindex surely is useful!

Answer 1

To make any element focusable, not only interactive content ones, you have to set tabindex attribute.

In your sample, it would be:

<div id='myeditdiv' contenteditable='true'>
  <span class='foo_cl' tabindex="-1">FOO<span class='bar_cl' tabindex="-1">bar</span</span>
</div>

Note: negative tabindex makes element focusable but not tabbable because using tabbing method would start at 0 using absolute value (spec).

Now in jQuery, you could delegate focus event to these elements:

$('[contenteditable]').on('focus', '*', function(e){
    e.stopPropagation();
    console.log(this);
});

-jsFiddle-

As a side note, jQuery UI has a :focusable pseudo selector. If you wish to dynamically set tabindex attribute to not focusable elements, you could use:

$('[contenteditable]').find(':not(:focusable)').attr('tabindex', -1);

-jsFiddle (including jQuery UI)-

If you don't want to include jQuery UI just to get :focusable pseudo selector, you can create your own custom selector:

//include IIFE if not already including jQuery UI
(function () {
    function focusable(element, isTabIndexNotNaN) {
        var map, mapName, img,
        nodeName = element.nodeName.toLowerCase();
        if ("area" === nodeName) {
            map = element.parentNode;
            mapName = map.name;
            if (!element.href || !mapName || map.nodeName.toLowerCase() !== "map") {
                return false;
            }
            img = $("img[usemap='#" + mapName + "']")[0];
            return !!img && $(img).is(':visible');
        }
        return (/^(input|select|textarea|button|object)$/.test(nodeName) ? !element.disabled :
            "a" === nodeName ? element.href || isTabIndexNotNaN : isTabIndexNotNaN) &&
        // the element and all of its ancestors must be visible
        $(element).is(':visible');
    }
    $.extend($.expr[":"], {
        focusable: function (element) {
            return focusable(element, !isNaN($.attr(element, "tabindex")));
        }
    });
})();

-jsFiddle-