function open_url(user_url){	
	document.main_menu.action=user_url;
	document.main_menu.target="_top";
	document.main_menu.submit();
}

function open_content(user_url){
	document.main_menu.CONTENT_URL.value=user_url;
	document.main_menu.action="./first.php";
	document.main_menu.target="_top";
	document.main_menu.submit();
}

function bbs_pop(target_url){	  
	  window.open(target_url, 'hs_bbs', 'width=750,height=600,left=100,top=10,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes');
}