function menu(menu_num){

	menu_link=document.getElementById('main_menu').getElementsByTagName('a');
	menu_status=menu_link[menu_num];
	links_num=menu_link.length;

	menu_block=document.getElementById('info');
	block_style=menu_block.style;

	if(menu_status.className=='active'){
		menu_status.className='';
		block_style.display='none';

	}

	else{
		var i=0;
		while(i<links_num){
			menu_link[i].className='';
			i++;
		}

		menu_status.className='active';

		if(menu_num<links_num-1){
			block_style.left=menu_link[menu_num+1].offsetLeft-497+'px';
		}

		else{
			block_style.left=366+'px';
		}

		block_style.display='block';
		menu_block.innerHTML=document.getElementById('info_'+menu_num).innerHTML;
	}
}