Unika rader, så ajax förstår vilken rad man uppdaterar.

Hej, hur får jag varje rad att bli unik? så om jag skriver i rad 8 så uppdateras bara den raden? kan man binda dom unikt på något sätt?

function showTimar(){
 var ajaxRequest;  // The variable that makes Ajax possible!
	
 try{
   // Opera 8.0+, Firefox, Safari
   ajaxRequest = new XMLHttpRequest();
 }catch (e){
   // Internet Explorer Browsers
   try{
      ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
   }catch (e) {
      try{
         ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
      }catch (e){
         // Something went wrong
         alert("Your browser broke!");
         return false;
      }
   }
 }
 // Create a function that will receive data 
 // sent from the server and will update
 // div section in the same page.
 ajaxRequest.onreadystatechange = function(){
   if(ajaxRequest.readyState == 4){
      var ajaxDisplay = document.getElementById('timar');
      ajaxDisplay.innerHTML = ajaxRequest.responseText;
   }
 }
 // Now get the value from user and pass it to
 // server script.

 var tart = document.getElementById('tart').value;
 
 var queryString = "?tart=" + tart ;
 ajaxRequest.open("GET", "2.php" + 
                              queryString, true);
 ajaxRequest.send(null); 
}

$i = 1;
echo $_REQUEST['tart'];
while($i<=10) {
	if(isset($_REQUEST['tart'])) {
		$idd = $_REQUEST['tart'];
echo '<input type="text" name="ttart" id="tart" class="field" onchange="showTimar(this.value, ' . $i . ')" value="'. $idd . '" /><br>';
	}
	else {
echo '<input type="text" name="ttart" id="tart" class="field" onchange="showTimar(this.value, ' . $i . ')" /><br>';
	}
$i++;
}