<script type="text/javascript">
$(function()
{
  var x = 0;
  
  function next()
  {
    alert(2);
    alert(x);
  }
  
  $.getJSON('./index.php?cmd=json', function(data)
  {
    x = data.a;
    
    alert(1);
    alert(x);
    
    next();
  });

});
</script>