Calling a function on bootstrap modal open

Bootstrap modal exposes events. Listen for the the shown event like this

$('#my-modal').on('shown', function(){
  // code here
});

you can use show instead of shown for making the function to load just before modal open, instead of after modal open.

$('#code').on('show.bs.modal', function (e) {
  // do something...
})

will not work.. use $(window) instead

For Showing

$(window).on('shown.bs.modal', function() { 
    $('#code').modal('show');
    alert('shown');
});

For Hiding

$(window).on('hidden.bs.modal', function() { 
    $('#code').modal('hide');
    alert('hidden');
});

You can use the shown event/show event based on what you need:

$( "#code" ).on('shown', function(){
    alert("I want this to appear after the modal has opened!");
});

Demo: Plunker

Update for Bootstrap 3.0

For Bootstrap 3.0 you can still use the shown event but you would use it like this:

$('#code').on('shown.bs.modal', function (e) {
  // do something...
})

See the Bootstrap 3.0 docs here under "Events".