live-ajax-editor.js

(function() {
  window.xhrs = [];
  var tmpSend = XMLHttpRequest.prototype.send,
      tmpSetRequestHeader = XMLHttpRequest.prototype.setRequestHeader,
      tmpOpen = XMLHttpRequest.prototype.open;

  XMLHttpRequest.prototype.open = function(type, url, async, user, pass) {
    this._requestHeaders = [];
    this._openArgs = arguments;

    // this.theRequestUrlAndType = type + ' ' + url
    //   + (user || pass ? ' (' + user + ' / ' + pass + ')' : '');
    return tmpOpen.apply(this, this._openArgs);
  };

  XMLHttpRequest.prototype.setRequestHeader = function() {
    this._requestHeaders.push(arguments);
    return tmpSetRequestHeader.apply(this, arguments);
  };

  XMLHttpRequest.prototype.send = function(/* data is arguments[0] */) {
    var t = this;
    var args = arguments;
    t._edit = function() {
      t._openArgs[1] = prompt("Confirm XHR url:\n" + t._openArgs[1], t._openArgs[1]) || t._openArgs[1];
      var newData = prompt("Confirm XHR data for:\n" + t._openArgs[1], (args[0] == null ? '' : args[0]) );
      if(newData === null)
        return;
      args[0] = newData;
      
      var xhr = new XMLHttpRequest();
      xhr.open.apply(xhr, t._openArgs);
      
      if(t._requestHeaders && this._requestHeaders.length) {
        t._requestHeaders.forEach(function(headerArgs){
          tmpSetRequestHeader.apply(xhr, headerArgs);
        });
      }
      
      return xhr.send.apply(xhr, args);
    };
    xhrs.push(t);
    console.log("xhrs[" + (xhrs.length-1) + "]._edit() to resend with new data", args);

    return tmpSend.apply(t, args);
  };
})();