how to get data from server in unity

hi! in my game i have to get some data from my server. i used WWW class to do this. but i don't know to transfer any data from the server we have to generate JSON file or no!!! can anyone help me?? i also write a snippet of code to download some string from server i don't know how to fix it. using UnityEngine; using System.Collections; using LitJson;

 public class JSON_D : MonoBehaviour{
     public static JSON_D staticOBJ;
     public static parseJSON parsejson;
     public WWW www;
     void Start()
     {
         staticOBJ = this;
         staticOBJ.function();
     }
     public void function()
     {
         StartCoroutine(getData());
     }
     protected IEnumerator getData()
     {
 
         string url = "any url in any website. doesn't matter";
         //WWW www = new WWW(url);
         this.www = new WWW(url);
         yield return www;
         if (www.error == null)
         {
             Debug.Log(www.text);
         }
         else
         {
             Debug.Log("ERROR: " + www.error);
         }
     }

and another code exist in server to serve it.

 //after retrieving data from database :
 
 echo $names ." ". $record
 
 ?>