docs: function preventZoom() {
          var formFields = document.querySelectorAll('input, select, textarea'),
              contentString = 'width=device-width,initial-scale=1,maximum-scale=',
              i = 0;
  
          if (!viewportmeta) {
              return;
          }
  
          for (; i < formFields.length; i += 1) {
              formFields[i].onfocus = function() {
                  viewportmeta.setAttribute('content', contentString + '1');
              };
  
              formFields[i].onblur = function () {
                  viewportmeta.setAttribute('content', contentString + '10');
              };
          }
      }