Create List Item Using JavaScript Object Model (JSOM)

CreateListItemJSOM.js

function createListItem() {
  var clientContext = SP.ClientContext.get_current();
  var website = clientContext.get_web();
  var oList = website.get_lists().getByTitle('WebKnowledgeZone');
  var itemCreateInfo = new SP.ListItemCreationInformation();
  this.oListItem = oList.addItem(itemCreateInfo);
  oListItem.set_item('Title', 'My New Item!');
  oListItem.update();
  clientContext.load(oListItem);
  clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));
}

function onQuerySucceeded() {
  alert('Item created: ' + oListItem.get_id());
}

function onQueryFailed(sender, args) {
  alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}