code: function fillForm(page, ph, selectorAndValue, callback) {
      page.evaluate(function (selectorAndValue) {
          try {
              var selector = selectorAndValue[0];
              var value = selectorAndValue[1];
              document.querySelector(selector).value = value;
              return null;
          } catch (error) {
              return error;
          }
      }, function (error) {
          // do this because if there is no error, the error is still something so we can't simply do callback(error, page, ph);
          if (error) {
              callback(error, page, ph);
              return;
          }
          callback(null, page, ph);
      }, selectorAndValue);
  }
docs: Fills a form on the page
  @param page
  @param ph
  @param {Array} selectorAndValue index 0 - {string} selector
  index 1 - {string} value
  @param {pageCallback} callback