This is an example of how you could make a service call to multiple appids, exiting on the first one that succeeds

spaz-webos-servicecall.js

function callSpaz(serviceParams, onFailure) {

	var appids = ['com.funkatron.app.spaz-sped', 'com.funkatron.app.spaz', 'com.funkatron.app.spaz-beta'], index = 0;

	function makeCall() {
		if (index < appids.length) {

			Mojo.Log.info('Trying to post with appid %s', appids[index]);

			var request = new Mojo.Service.Request("palm://com.palm.applicationManager", {
				method: 'launch',
				parameters: {
					id: appids[index],
					params: serviceParams
				},
				onFailure: function() {
					Mojo.Log.info('Failed to post with appid %s', appids[index]);
					index++; // go to next appid
					makeCall(); // retry
				}.bind(this)
			});

		} else {
			Mojo.Log.error('Failed to post to Spaz');
			if (onFailure) {
			    onFailure(serviceParams);
			}
		}

	}
        makeCall();


}