Download csv File using Visual force page

I tried downloading a csv file from a visualforce page.

In the code below i am querying contacts object and downloading the query result in csv

 {!a.FirstName},{!a.lastName}

Apex Class:

public class Sample
{   
    public List contacts {get;set;}
    public pageReference fetch()
    {
         contacts = [SELECT Id,firstname,lastname FROM Contact limit 20];
        return null;
    }    
}

Display Matrix Report in Visualforce page

Using the jsforce i recently worked on analytics to display Matrix reports in visualforce page. Querying the tabular Report and accessing the fields and displaying in visualforce pages.

Display reports in visualforce page

Using the jsforce i recently worked on analytics to display reports in visualforce page. Querying the tabular Report and accessing the fields and displaying in visualforce pages.

Create Sobject Records from JavaScript using Jsforce Library

Create a vf page and past the below code