(function($) {
	$.fn.changeBackground = function(options)
	{
		var defaults = {
				classToSwitch : ['container-1', 'container-2', 'container-3']
		};
		
		var options = Psa.$.extend(defaults, options);
		
		return this.each(function(){
			var container = $(this);
			var longueur = options.classToSwitch.length;
			var index = Math.floor(Math.random()*longueur);
			container.addClass(options.classToSwitch[index]);
		});
	};
})(jQuery);