json jquery php question

Question

i dont understand one thing.

if i want to get JSON data (key-value-pairs) from php to jquery using ajax...which of these following ones should i use?

• $.get
• $.post
• $.getJSON

do i need to use getJSON if i want to use json_encode in php file? but what if i want to send with post? (there is no postJSON)?

and one more thing:

in php file i wrote:

<?php
  if($_GET['value'] == "value")
  {
  $array['firstname'] = 'Johnny'; 

  $jsonstring=json_encode($array); 

  return $jsonstring; 
  }
?>

in jquery file

  $.getJSON("php.php", {value: "value"}, function(data){
   alert(data.firstname);
  });

why doesnt this work??:S

Answer 1

The problem lies with the line in PHP:

return $jsonstring;

You should echo it instead:

echo $jsonstring;

As for which jQuery method to use, I suggest $.getJSON() if you can return a pure json string. It really depends on how you use it.

When using $.getJSON(), your server file should return a JSON string. Thus echoing the string returned by json_encode() would be appropriate for the $.getJSON() method to take in the response.

Answer 2

You can use .ajax, this allows you to do both get and post.

Answer 3

I always use $.ajax.

$.ajax({
     url: "script.php",
     type: "POST",
     data: { name : "John Doe" },
     dataType: 'json',
     success: function(msg){
        alert(msg);
     }
});

in PHP:

$name = $_POST['name']
echo $name

this will alert "John Doe"

also, if it's not working, use firebug to see values being passed around.