var Clicable = new Class({
	initialize: function(class_name, filled_class) {
		this.class_name = class_name;
		this.filled_class = filled_class;
		this.setActionHandlers();
	}
});

Clicable.implement({
	setActionHandlers: function() {
		
		var obj = this;
		
		$$('.' + this.class_name).each(function(input){
			input.addEvent('focus', function(){
				if(this.value == this.title) {
					this.value = '';
					this.addClass(obj.filled_class);
				}
			});
			
			input.addEvent('blur', function() {
				if(this.value == '') {
					this.value = this.title;
					this.removeClass(obj.filled_class);
				}
			});
		});
	}
});