Tooltron

(function($) {

    $.fn.prepopulate = function(dependencies, maxLength) {

        /*

            Depends on urlify.js

            Populates a selected field with the values of the dependent fields,

            URLifies and shortens the string. 

            dependencies - array of dependent fields id's 

            maxLength - maximum length of the URLify'd string 

        */

        return this.each(function() {

            var field = $(this);

            field.data('_changed', false);

            field.change(function() {

                field.data('_changed', true);

            });

            var populate = function () {

                // Bail if the fields value has changed

                if (field.data('_changed') == true) return;

                var values = [];

                $.each(dependencies, function(i, field) {

                  if ($(field).val().length > 0) {

                      values.push($(field).val());

                  }

                })

                field.val(URLify(values.join(' '), maxLength));

            };

            $(dependencies.join(',')).keyup(populate).change(populate).focus(populate);

        });

    };

})(django.jQuery);