Dynamically loading javascript

dynamic.html

<span class="foo">bar</span>

dynamic.js

/* So often asked, so here you go! */
var url = 'http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js';
    
var xhr = new XMLHttpRequest();  // send the HTTP request for the JS file
xhr.onload = function() {
  eval(this.responseText);  // load it by applying eval on the string
  $('.foo').html('baz');  // jQuery land!
}
xhr.open('GET', url);
xhr.responseType = 'text';
xhr.send();