I want to create a hello world json rest webservice in test.php:
  <?php header("Content-type: application/json; charset=utf-8");
     $test[] = "hello";  
     $test[] = "world";  
    $json = json_encode($test);
    echo $json;    
  ?>
But nothing is returned when I test it with ajax below why ?
<html>
<head>
<script>
function test()
{ 
    var xhr; 
    try {  xhr = new ActiveXObject('Msxml2.XMLHTTP');   }
    catch (e) 
    {
        try {   xhr = new ActiveXObject('Microsoft.XMLHTTP');    }
        catch (e2) 
        {
          try {  xhr = new XMLHttpRequest();     }
          catch (e3) {  xhr = false;   }
        }
     }
    xhr.onreadystatechange  = function()
    { 
         if(xhr.readyState  == 4)
         {
              if(xhr.status  == 200) 
                  alert(xhr.responseText); 
              else 
                 alert("Error code " + xhr.status);
         }
    }; 
   xhr.open(GET, "test.php",  true); 
   xhr.send(null); 
} 
</script>
</head>
<body>
<script>
test();
</script>
 </body>
 </html>