Difference in clientContext.executeQueryAsync(Function.createDelegate(this, this.success) vs clientContext.executeQueryAsync(success)

What is basic difference between the below way of declaring the callback method in Sharepoint:

clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));

VS

clientContext.executeQueryAsync(onQuerySucceeded);