Try this;
var d = new Date("2014-03-24");
d.toLocaleDateString("en-US"); // "3/24/2014"
Note that the advantage here is that you can pass through different locales for different formats such as "en-GB" for the UK for instance which would give you day/month/year. And if you want it really specifically with a two-digit month;
d.toLocaleDateString("en-US", {day:'2-digit', month:'2-digit', year:'numeric'}); // "03/24/2014"
If you run into browser inconsistencies, you can also do this old-school lowest-common-denominator with;
(d.getMonth()+1) + "/" + d.getDate() + "/" + d.getFullYear(); // "3/24/2014"
But that won't pad your day and month with 2-digit numbers though. If you want that, you'll need to use a small pad function like this;
function padDateZ(n) { return n < 10 ? '0' + n : n.toString(); }
(padDateZ(d.getMonth()+1)) + "/" + padDateZ(d.getDate()) + "/" + d.getFullYear(); // "03/24/2014"