jQuery on() and stopPropagation()

I have a side pane that slides in from the left, adding content dynamically with get(). I want all clicks outside the pane to cause it to close by triggering a function. Based on other questions I read, I came up with the following code.

$('html').click(function() {
    if (side_showing) {
        close_side();
    }
});

$(document).on("click", "#side", function(event) {  
    event.stopPropagation();
});

I can't seem to make it work. I know that the on() function is being triggered, but event.stopPropagation doesn't seem to be. Any tips?