remove appended script javascript

how can I remove my appended script because it causes some problems in my app.

This is my code to get my script

var nowDate = new Date().getTime();
var url = val.redirect_uri + "notify.js?nocache=" + nowDate + "&callback=dummy";
var script = document.createElement('script');
script.src = url;
document.body.appendChild(script);

Then I have an auto load function, that causes to create another element script.

I want to get rid of the previous element that was appended before another element is added.