I guess there's a number of ways to do this. Here's one :
$(function () {
var getscriptlist = ['js/libs/handlebars.js', 'js/libs/ember.js', 'js/libs/prefixfree.js'];
var deferreds = [ $.Deferred() ];//<<<<<< start the array with a special Deferred
$(window).on('load', deferreds[0].resolve);//<<<<<< resolve the special Deferred when the page has loaded
for (var i = 0; i < getscriptlist.length; i++) {
deferreds.push($.getScript(getscriptlist[i]));
}
$.when.apply($, deferreds).then(function () {
//code here will run when all Deferreds/promises in the array become resolved.
});
});