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Archive for April, 2009

Loading a page into a dialog

April 18th, 2009

I previously showed the basic usage of the jQuery UI dialog.  In this article, I’ll show how to open a page in a dialog.  We’ve all been to sites where there’s a help link that opens a popup with some short help text.  This is usually done with a simple window.open call attached to the click event of the link.

<a id="page-help" href="page.html" onclick="window.open(this.href, 'popupwindow', 'width=500,height=300'); return false;">what is this?</a>

Making it better

The one thing that this code has going for it is that users without JavaScript will still be able to get to the page with the help content. Of course, a better implementation would move the JavaScript out of the HTML, properly separating content from behavior.  We can spruce this up by loading the content into a dialog instead of a new window:

$(document).ready(function() {
	$('#page-help').each(function() {
		var $link = $(this);
		var $dialog = $('<div></div>')
			.load($link.attr('href'))
			.dialog({
				autoOpen: false,
				title: $link.attr('title'),
				width: 500,
				height: 300
			});

		$link.click(function() {
			$dialog.dialog('open');

			return false;
		});
	});
});

How it works

We’re finding the link, loading the contents of the linked page into a div and creating a dialog from that div.  We then bind a click event to the link to show the dialog.  This code by itself will work in many situations.  However, the page you’re linking to may have a heading that you’re already reproducing with the dialog title.  There may also be other elements on the page that won’t make sense in a popup, such as navigational elements or a page footer.  Luckily the .load() function allows us to pass in a selector to find the contents that we care about.  In this example we’ll assume the main content of the page is in a div with an id of content.

$(document).ready(function() {
	$('#page-help').each(function() {
		var $link = $(this);
		var $dialog = $('<div></div>')
			.load($link.attr('href') + ' #content')
			.dialog({
				autoOpen: false,
				title: $link.attr('title'),
				width: 500,
				height: 300
			});

		$link.click(function() {
			$dialog.dialog('open');

			return false;
		});
	});
});

View this example in a new window

jQuery UI - Dialog , , ,

Basic usage of the jQuery UI dialog

April 8th, 2009

The jQuery UI dialog, like many jQuery UI plugins, is extremely easy to get started with but has a few areas that causes new users some trouble.  One of the most commonly asked questions on the jquery-ui list is “Why does my dialog only open once?”  In this article I’ll explain the problem these users are running into and how to get your dialogs to show each and every time.

Problem:

All jQuery UI plugins maintain state, such as the current option values, whether the plugin is enabled or disabled, which plugins have been initialized on the element, etc.  This state persists from the time the plugin is instantiated on the element until it is destroyed, either explicitly by the user calling .pluginName('destroy') or by removing the element (or one of its ancestors) via .remove().  Because of this state management, you cannot instantiate the same plugin on an element multiple times, unless you destroy the plugin instance first.

The problem that users often encounter with dialogs is that they try to instantiate a new dialog every time the user performs some action (generally clicking a link or a button).  This is an understandable mistake because at first glance it seems like calling .dialog() on an element is what causes the dialog to open.  In reality what is happening is that a new dialog instance is being created and then that instance is being opened immediately after instantiation.  The reason that the dialog opens is because dialogs have an autoOpen option, which defaults to true.  So when a user calls .dialog() on an element twice, the second call is ignored because the dialog has already been instantiated on that element.

Solution:

The simple solution to this problem is to instantiate the dialog with autoOpen set to false and then call .dialog('open') in the event handler.

$(document).ready(function() {
	var $dialog = $('<div></div>')
		.html('This dialog will show every time!')
		.dialog({
			autoOpen: false,
			title: 'Basic Dialog'
		});

	$('#opener').click(function() {
		$dialog.dialog('open');
		// prevent the default action, e.g., following a link
		return false;
	});
});

View this example in a new window

jQuery UI - Dialog , , , , , ,