Runner.js

// runner
function Runner() {
	this.descriptionDefer = $.Deferred();
	this.descriptionPromise = this.descriptionDefer.promise();
}

Runner.prototype.stop = function() {
	this.descriptionDefer.resolve(this.descriptionDefer);
}

Runner.prototype.runSequentially = function(steps){
	var self = this;
	var stepCounter = 0;
	self.descriptionDefer.then(null, null, function(){
		if (stepCounter == steps.length){
			self.descriptionDefer.resolve(self.descriptionDefer);
		} else {
			steps[stepCounter](self.descriptionDefer);
			stepCounter++;
		}
	});
	self.descriptionDefer.notify(); // start first step
	
	return self.descriptionPromise;
}


function descr_welcomeModal(mydefer){
	setTimeout(function(){
		// backdrop has issue due to positioning + it doesn't look too good on the page
		$('#welcomeModal').modal({backdrop: false}); 
		$('#welcomeModal').on('hidden', function (){
			mydefer.notify();
		});
	}, 500);
}