django-admin2/djadmin2/static/themes/bootstrap/js/actions.js

$(function() {
	var element = $("#model-list");
	var selectAllCheckbox = element.find('.model-select-all');
	var selectCheckboxen = element.find('.model-select');
	var selectedCount = element.find('#selected-count');

	var updateSelectedCount = function() {
		var count = 0;
		for (var ix = 0; ix < selectCheckboxen.length; ix++) {
			if ($(selectCheckboxen[ix]).prop('checked')) {
				count++;
			};
		};
		selectAllCheckbox.prop('checked', count == selectCheckboxen.length);
		selectedCount.text(count);
	};

	selectAllCheckbox.click(function(e) {
		selectCheckboxen.prop('checked', this.checked);
		updateSelectedCount();
	});

	selectCheckboxen.click(function(e) {
		updateSelectedCount();
	});
});