Source Map Bookmarklet

gistfile1.js

javascript: void(
    (function (global, oDOC, handler) {
      var head = oDOC.head || oDOC.getElementsByTagName('head');
  
      function LABjsLoaded() {
          window.sourceMapSupport.install();
      }
  
      // loading code borrowed directly from LABjs itself
      setTimeout(function () {
          if ('item' in head) { // check if ref is still a live node list
              if (!head[0]) { // append_to node not yet ready
                  setTimeout(arguments.callee, 25);
                  return;
              }
              head = head[0]; // reassign from live node list ref to pure node ref -- avoids nasty IE bug where changes to DOM invalidate live node lists
          }
          var scriptElem = oDOC.createElement('script'),
              scriptdone = false;
          scriptElem.onload = scriptElem.onreadystatechange = function () {
              if ((scriptElem.readyState && scriptElem.readyState !== 'complete' && scriptElem.readyState !== 'loaded') || scriptdone) {
                  return false;
              }
              scriptElem.onload = scriptElem.onreadystatechange = null;
              scriptdone = true;
              LABjsLoaded();
          };
          scriptElem.src = 'https://raw.githubusercontent.com/evanw/node-source-map-support/master/browser-source-map-support.js';
          head.insertBefore(scriptElem, head.firstChild);
      }, 0);
  
      // required: shim for FF <= 3.5 not having document.readyState
      if (oDOC.readyState == null && oDOC.addEventListener) {
          oDOC.readyState = 'loading';
          oDOC.addEventListener('DOMContentLoaded', handler = function () {
              oDOC.removeEventListener('DOMContentLoaded', handler, false);
              oDOC.readyState = 'complete';
          }, false);
      }
  })(window, document);
);