Passing JSON object from php to JS via Ajax - php

Question

I am trying to pass a JSON object from a php script to a Javascript file with Ajax. The code below worked for a simple string, but I am now trying to amend it to work with multiple strings contained within a JSON object. I have pasted extracts of each file below. What am I doing wrong?
This is a extract from the html/javascript file which is creating the request...
function retrieveAircraftInfo(str) {
var xmlhttp;
if (str.length==0) {
document.aircraftRegForm.aircraftManufacturer.value="";
return;
}
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp = new XMLHttpRequest();
} else {
// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState==4) {
var aircraftDataJSON = xmlhttp.responseText.evalJSON();
document.aircraftRegForm.aircraftManufacturer.value = aircraftDataJSON.manufacuter;
document.aircraftRegForm.aircraftType.value = aircraftDataJSON.type;
document.aircraftRegForm.aircraftPopularName.value = aircraftDataJSON.popularName;
document.aircraftRegForm.aircraftGenericName.value = aircraftDataJSON.genericName;
}
}
xmlhttp.open("GET","scraper.php?q="+str,true);
xmlhttp.send();
}
This is an extract from the php file which is doing the database search:
$aircraftDataArray = array("manufacturer" => $extractedManufacturer,
"type" => $extractedType,
"popularName" => $extractedPopularName,
"genericName" => $extractedGenericName);
echo json_encode($aircraftDataArray);

Answer 1

Try
var aircraftDataJSON = JSON.parse(xmlhttp.response);
Otherwise, check in the console of the developer tools if PHP returns some error.
Your JS example worked for me with JSON.parse