Ajax kullanarak yapabilirsin. Hali hazırda Jquery de kullandığı varsayarak örnek veriyorum:
index.php
<html>
<head>
    <title>Test</title>
    <script src="http://code.jquery.com/jquery-latest.min.js"></script>
    <script>
        function bilgial(btn) {
            $.ajax({
                url: "post.php",
                method: "POST",
                data: "id=" + $(btn).data("id"),
                success: function (gelen) {
                    $("#test").html("");
                    $("#test").append("<p><b>id: </b> "+gelen.id+"</p>")
                    $("#test").append("<p><b>isim: </b> "+gelen.isim+"</p>")
                    $("#test").append("<p><b>website: </b> "+gelen.website+"</p>")
                }
            });
        }
    </script>
</head>
<body>
<div id="test"></div>
<button onclick="bilgial(this)" data-id="86">86 ID'li veriyi getir.</button>
</body>
</html>
post.php
<?php
header('Content-Type: application/json');
$mysqldanGelenler = ["id"=>86,"isim"=>"Samed","website"=>"r10.net"];
echo json_encode($mysqldanGelenler);
?>