JavaScript with Molly

Molly uses device detection to decide whether or not a device should be given JavaScript or not.

Adding JavaScript to your app

The single most important thing to remember when adding JS functionality to your app is that of graceful degradation. Not all devices that Molly supports support JS - the Supported Devices page gives the full breakdown.

Molly comes with JQuery 1.2.6 (Symbian 9.4 struggles on newer versions), so this is available for you to use if you would like.

Putting JavaScript into page headers is not supported, as this will not work when the page is asynchronously loaded. All JavaScript must be put in a file called static/APP/js/smart.js (where APP is the name of your application package), which will be included automatically on every page of the site, as well as being minified and collated into one large file when served.

As your JS will be loaded on every page, it is important not to do anything that may interfere with other pages. The section below covers this in more detail.

JavaScript with the asynchronous page loading framework

Because of the AJAX added to Molly in 1.1, JavaScript is not quite as straight forward as it used to be. As multiple pages can be loaded and rendered within the same session using AJAX, the document.ready event can not be relied upon to set up any functionality in your page.

To work around this, Molly provides a new event which is called when an AJAX page change is triggered: ‘molly-page-change’, with one argument, the URL of the new page. You will then probably want to check the url attribute to ensure that it’s a page that you should be handling.

$(document).bind('molly-page-change', function(event, url){
    if (url == '/my-app/') {
        /* Set up my event handlers here */

Anything that would be in a document.ready handler or a <script> tag in the head will then need to go on there. This event also get’s called on the first page load, so you can put everything that you will ever need to handle in there.

If you do things like set up timers in the event handler, you will also have to remember to clear those timers if the page transitions to another page.

If you add your own AJAX handlers to redraw the page, etc, you will then be responsible for ensuring the listeners are set up on any <a> and <form> elements you create. Fortunately, this is quite simple - just call ‘capture_outbound()’ at the end of your AJAX callback and the correct event listeners will be created.

To suppress the default action of AJAX page transitions, returning false or similar is not enough to stop the default page transition happening. To do this, you must add an ‘has-ajax-handler’ class to any links and forms you want your code to handle, before the ‘capture_outbound()’ function is called. If you add this class whilst inside the ‘molly-page-change’ event handler, then you don’t need to worry any further, as this is automatically called after the event has been triggered.

Catching location changes

It is also possible to catch occasions when the user updates their location, or the location is updated for them automatically by listening to an event in a similar way. You may want to do this to, for example, trigger a refresh of location-specific data.

The event to listen to is on the document object, and is ‘molly-location-update’.

$(document).bind('molly-location-update', function(){
    /* react to how the location changed here */