As Eric Aya mentioned in his comment. The issue is that your PHP service spits out the JSON data into an HTML page.
When I view source of your page I get the following:
<html>
[{"ID":"1","Name":"Peter"},{"ID":"2","Name":"James"}]
</html>
The page source of the w3schools url is simply JSON. In your PHP service, output your data in JSON and you should be good to go.