Pass JSON AJAX reply to PHP - php

Question

I have a script which uses AJAX to connect to a PHP script which queries a database and returns some values. The code of which is below:
<script>
function showUser(str)
{
if (str=="")
{
document.getElementById("txtHint").innerHTML="";
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 && xmlhttp.status==200)
{
document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","ajaxphp.php?ID="+str,true);
xmlhttp.send();
}
</script>
<select id="users" name="users" onchange="showUser(this.value)">
<option value="">Select a person:</option>
<!-- PHP populates this dropdown box -->
</select>
<div id="txtHint"><b>Selected user info will be listed here.</b></div>
Right now the txtHint div will return anything the ajaxphp.php script prints. This isn't very flexible, however. What I want to do is create an array in ajaxphp.php and use json_encode() to pass the results back.
The problem I'm having is I don't know how to get the original script to grab the results so I can do useful things with them. Right now I can make it return a JSON array which will appear in the txtHint div but I've no idea how to get PHP to actually read that information so I can do something with it.

Answer 1

Try using jQuery Ajax...
$.ajax({
url : 'ajaxphp.php?ID='+str,
type: 'get',
dataType:'json',
success : function(data) {
console.log(data);
}
});
Data in success function parameter is your encoded result that you return from php.
echo json_encode($result);
Then you can access it with something like this from javascript.
data.result1
data.result2
data.result3....

Answer 2

Use $_GET method to See what ever the user send you in php see here:
http://php.net/manual/en/reserved.variables.request.php

Answer 3

Maybe the json_decode() php method is the solution of what you want.
http://www.php.net/manual/en/function.json-decode.php
This method takes a JSON encoded string (from the json_encode method for example) and converts it into a PHP variable... so you can use this variable like an object and simply access to its attributes.
Maybe this other post will help you : How to decode a JSON String with several objects in PHP?
Hope this helps ! Bye !