Detect Global Variables

globals.js

(function(){
  var differences = {},
    ignoreList = (prompt('Ignore filter (comma sep)?', 'jQuery, Backbone, _, $').split(/,\s?/) || []),
    iframe = document.createElement('iframe'),
    count = 0; ignoreList.push('prop');

  for (prop in window) {
    differences[prop] = {
      type: typeof window[prop],
      val: window[prop]
    }; count++;
  }

  iframe.src = 'about:blank';
  iframe.style.display = 'none';
  document.body.appendChild(iframe);
  iframe = iframe.contentWindow || iframe.contentDocument;

  for (prop in differences) {
    if (prop in iframe || ignoreList.indexOf(prop) >= 0) {
      delete differences[prop];
      count--;
    }
  }

  console.info('Total globals: %d', count);
  return differences;
})();