function ly_functions()
{
	var app = this;

	app.removeClass = function(old, remove)
	{
		var classes;
		var i;
		var f = null;

		classes = old.split(' ');
		for (i = 0; i < classes.length; i++)
		{
			if (classes[i] == remove) f = i;
		}
		if (f != null) classes.splice(f, 1);
		return(classes.join(' '));
	}

	app.replaceClass = function(old, toreplace)
	{
		var classes;
		var i;
		var f = null;

		classes = old.split(' ');
		for (i = 0; i < classes.length; i++)
		{
			if (classes[i] == toreplace) f = i;
		}
		if (f != null) classes[f] = toreplace;
		return(classes.join(' '));
	}

	app.addClass = function(old, toadd)
	{
		var classes;
		var i;
		var f = null;

		classes = old.split(' ');
		for (i = 0; i < classes.length; i++)
		{
			if (classes[i] == toadd) f = i;
		}
		if (f == null) classes.push(toadd);
		return(classes.join(' '));
	}

	app.hasClass = function(classname, classes)
	{
		var class_strings;
		var i;

		class_strings = classes.split(' ');
		for (i = 0; i < class_strings.length; i++)
		{
			if (class_strings[i] == classname) return(true);
		}
		return(false);
	}

	app.replaceImage = function(elem_id, img_src)
	{
		if (document.getElementById)
		{
			var elem = document.getElementById(elem_id);
			if (elem)
			{
				elem.src = img_src;
			}
		}
	}
}