Question

Is there a way to test if a custom attribute is a function? I’ve tried using jquery’s isFunction method, but it doesn’t seem to work with this scenario.

For example:

<input id="test" class='date' oncomplete="function() { alert('i am a function'); }" type="text" />

<script>
    $(".date").livequery(function () {
        var onComplete = $(this).attr("oncomplete");
        if ($.isFunction(onComplete)) {
            $(this).mask("99/99/9999", { completed: onComplete });
        } else {
            $(this).mask("99/99/9999");
        }
    });
</script>

I have several date fields. I’m trying to give a couple of them special behavior. I know I can just have a separate jquery selector to set them up with the behavior they need. But wanted to see if there was an inline way of doing this.

Answer 1

When getting attributes from DOM elements, jQuery converts them to functions if they are DOM events (like onclick, onkeyup, etc.), but not if they are custom “events” (example: http://jsfiddle.net/FJWhp/1/).

I suggest NOT doing it this way. I suggest putting the function in your JavaScript, and use a data- attribute to store its name.

Like this:

<input id="test" class='date' data-complete="dateComplete" type="text" />

<script>
    function dateComplete() {
      alert('i am a function'); 
    }

    $(".date").livequery(function () {
        var onComplete = $(this).data("complete");
        if ($.isFunction(window[onComplete])) {
            $(this).mask("99/99/9999", { completed: window[onComplete] });
        } else {
            $(this).mask("99/99/9999");
        }
</script>

Or better yet, just have the function in JavaScript and don’t attach it to the DOM element at all.

<input id="test" class='date' type="text" />

<script>
    $(".date").livequery(function () {
        $(this).mask("99/99/9999", {
            completed: function(){
              alert('i am a function');
            }
        });
</script>