function addClass(_in) {
		var main = document.getElementById('main');
		var className;
		
		switch(_in){
			case 0:
				if(this.hasClass(main,'medium')) this.removeClass(main, 'medium');
				if(this.hasClass(main,'big')) this.removeClass(main, 'big');
				break;
			case 1:
				if(!this.hasClass(main, 'medium')) {
					if(this.hasClass(main, 'big')){
						this.removeClass(main, 'big');
					}
					main.className += "medium";
				}
				break;
			case 2:
				if(!this.hasClass(main, 'big')){
					if(this.hasClass(main, 'medium')){
						this.removeClass(main, 'medium');
					}
					main.className += "big";
				}
				break;																																	
		}
	}
	
	function hasClass(ele,cls) {
		return ele.className.match(new RegExp('(\\s|^)'+cls+'(\\s|$)'));
	}
	
	function removeClass(ele,cls) {
		if (hasClass(ele,cls)) {
			var reg = new RegExp('(\\s|^)'+cls+'(\\s|$)');
			ele.className=ele.className.replace(reg,' ');
		}
	}