function show_login() {
	document.getElementById('login').style.display = 'block';
	document.documentElement.style.overflowX = 'hidden';	 // horizontal scrollbar will be shown
    document.documentElement.style.overflowY = 'hidden';	 // vertical scrollbar will be shown
	}
	
    function hide_login() {
	document.getElementById('login').style.display = 'none';
	document.documentElement.style.overflowX = 'scroll';	 // horizontal scrollbar will be shown
    document.documentElement.style.overflowY = 'scroll';	 // vertical scrollbar will be shown
	}