Angular JS calculation based on input boxes

I read this thread: Simple Percentage Calculation of an Input Field with JQuery

But can't seem to get it to work for my situation. I have two input boxes, Wholesale and Sell Price, and I want to calculate the markup (difference) on the fly as the user is changing their Sell Price. I've built a simplified version of what I'm trying to do here:

http://ift.tt/1BkZbSy

And below is the JS - can anyone see what I'm doing wrong? Thanks!!

$(function() {
    
    // cache elements that are used at least twice
    var $sellprice = $("#SellPrice"),
        $markup = $("#markup"),
        $wholesale = $("#wholesale");
    
    // attach handler to input keydown event
    $sellprice.keyup(function(e){
        if (e.which == 13) {
            return;
        }
        var sellprice = parseFloat($sellprice.val()),
            markup = sellprice-wholesale;
        
        if (isNaN(sellprice)) {
            $markup.hide();
            return;
        }
        else {
        
        $markup.fadeIn().text(markup.toFixed(2));


        }
    });
   
});