I have recently posted another question which straight away users pointed me in the right direction.
$.ajax({
  type: 'POST',
  url: './',
  data: 'token=' + token + '&re=8',
  cache: false,
  timeout: 5000,
  success: function(html) {
    auth(html);
    var JSON_array = eval(html);
    alert(JSON_array[0].username);
  }
});
this returns the data correctly but I want to perform a kind of 'foreach'. the array contains data about multiple incoming and outgoing Instant Messages. So if a user is talking to more than one person at a time i need to loop through. the array's structure is as follows.
Array(
  [0] => Array
    (
      [username] => Emmalene
      [contents] => 
        <ul><li class="name">ACTwebDesigns</li><li class="speech">helllllllo</li></ul>
        <ul><li class="name">ACTwebDesigns</li><li class="speech">sds</li></ul>
        <ul><li class="name">ACTwebDesigns</li><li class="speech">Sponge</li><li class="speech">dick</li></ul>
        <ul><li class="name">ACTwebDesigns</li><li class="speech">arghh</li></ul>
    )
)
Any help very much appreciated.