window.addEvent('domready', function() { 
	$('main_table').getElements('img').each(function(image_id){
	image_id.addEvent('mouseenter', function(){
			this.set('opacity', 0.5);
			var source = image_id.getAttribute('id');
		});
			image_id.addEvent('mouseleave', function(){
			this.set('opacity', 1);
		});
	});
	$('main_table2').getElements('img').each(function(image_id){
	image_id.addEvent('mouseenter', function(){
			this.set('opacity', 0.5);
			var source = image_id.getAttribute('id');
		});
			image_id.addEvent('mouseleave', function(){
			this.set('opacity', 1);
		});
	});
});