jQuery / AJAX＆PHP域检查器

I'm trying to build a domain availability checker.

My PHP code is the following:

<?php

$domain = $_GET["domname"];

function get_data($url) {
    $ch = curl_init();
    $timeout = 5;
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    $data = curl_exec($ch);
    curl_close($ch);
    return $data;
}

$returned_content = get_data('http://freedomainapi.com/?key=XXXXXXX&domain=' . $domain);

echo $returned_content;

?>

When called as such: /domchek.php?domname=google.com

The JSON output is:

{"status":"success","domain":"google.com","available":true}

The JQuery im using to call the script is as follows:

$.get("domchek.php?domname=google.com", {data: "available"}, function(json) {
    $("html").html(json);
});

I just want to return the availability not the entire JSON output. I have tried json.availability and a number of other things but can't figure it out. Also if there is a better method for this than .get() please suggest it.

UPDATE:

$.getJSON("domchek.php?domname=google.com", function(json) {
  $("html").html(json.status);
});

The above works as does returning json.domain but trying to return json.available - which I require returns nothing..

Change this line:

$("html").html(json);

to:

$("html").html(json.status);

UPDATE: to force the GET request data type to JSON, change to:

$.get("domchek.php?domname=google.com", {data: "available"}, function(json) {
    $("html").html(json);
}, 'json');