async injectScript

In this function

function injectScript(src){
var s, t;
s = document.createElement('script'); s.type = 'text/javascript'; s.async = true; s.src = src;
t = document.getElementsByTagName('script')[0];
t.parentNode.insertBefore(s,t);
}

t is currently 'Undefined' so I cannot get the parentNode of it.

I am trying to use it like this

define([ 'jquery', 'jasmineJquery', 'require', 'async!http://maps.google.com/maps/api/js?sensor=false'], function(){
describe("Google test", function () {
it("should not throw exception ", function () {
.................
})
})
});

and run using sbt jasmine command