Nikolai Mavrenkov already created a good description of the problem on Stack Overflow: http://stackoverflow.com/questions/36893449/textarea-placeholder-isnt-shown-in-ie-11-being-rendered-using-react

I just can confirm it breaks in IE11, but works in IE10 (and other browsers) with React v15.0.2.

* @param {object} props
   * @return {string} Markup of opening tag.
   */
  _createOpenTagMarkupAndPutListeners: function(transaction, props) {
    var ret = '<' + this._currentElement.type;
    for (var propKey in props) {
      if (!props.hasOwnProperty(propKey)) {
        continue;
      }
      var propValue = props[propKey];
      if (propValue == null) {
        continue;
      }
      if (registrationNameModules.hasOwnProperty(propKey)) {
        if (propValue) {
          enqueuePutListener(this, propKey, propValue, transaction);
        }
      } else {
        if (propKey === STYLE) {
          if (propValue) {
            if (__DEV__) {
              
              this._previousStyle = propValue;
            }
            propValue = this._previousStyleCopy = Object.assign({}, props.style);
          }
          propValue = CSSPropertyOperations.createMarkupForStyles(propValue, this);
        }
        var markup = null;
        if (this._tag != null && isCustomComponent(this._tag, props)) {