filters.php

/**
 * Filter to check for CSRF attacks from the ajax requests.
 */
Route::filter('csrf_header', function()
{
  if (Session::token() != Request::header('x-csrf-token'))
	{
		throw new Illuminate\Session\TokenMismatchException;
	}
});

jquery-ajax.js

$.ajax({
  url: 'post/add',
  type: 'post',
  dataType: 'json',
  data: this.data,
  beforeSend: function(request) {
    return request.setRequestHeader("X-CSRF-Token", $("meta[name='token']").attr('content'));
  },
  success: function(ev) {

  },
  error: function(xhr, error, status) {

  }
});

layout.blade.php

<meta name="token" content="{{ Session::token() }}">