Populating the email field using URL parameters

NOTE: the "formFieldId" property will need to be updated to the correct value when implemented. (It will not be "emailField" by default).

/* Update the email field from URL parameter */
window._nvkForm = window._nvkForm || [];

var nvkUrlParameters = function () {
  var query_string = { };
  var query = window.location.search.substring(1);
  var vars = query.split("&");
  for (var i=0;i<vars.length;i++) {
    var pair = vars[i].split("=");
    if ( pair[0] ) {
      pair[0] = decodeURIComponent(pair[0]).replace('[]', '');
      if ( pair[1] ) {
        pair[1] = decodeURIComponent(pair[1]);
      }
      // If first entry with this name
      if (typeof query_string[pair[0]] === "undefined") {
        query_string[pair[0]] = pair[1];
        // If second entry with this name
      } else if (typeof query_string[pair[0]] === "string") {
        var arr = [ query_string[pair[0]],pair[1] ];
        query_string[pair[0]] = arr;
        // If third or later entry with this name
      } else {
        query_string[pair[0]].push(pair[1]);
      }
    }
  }
  return query_string;
}();

if ( nvkUrlParameters.email ) {
  window._nvkForm.push({
    on: 'load',
      updateField: function(fieldData) {      
          return { formFieldId: 'emailField', newValue: nvkUrlParameters.email };
    }
  });
}