function openBL(){
	document.getElementById('box-darkened').style.display='block';
	document.getElementById('box-light').style.display='block';
	$('box-light').setStyle('top', f_scrollTop() + Math.round(f_clientHeight() / 3));
	document.getElementsByTagName('html')[0].style.overflow='hidden';
	//window.scrollTo(0,0);
	$('box-darkened').setStyle('height', $('main_table_korak').offsetHeight);
}

function closeBL(){
	document.getElementById('box-darkened').style.display='none';
	document.getElementById('box-light').style.display='none';
	document.getElementsByTagName('html')[0].style.overflow='auto';
}

function f_clientHeight() {
	return f_filterResults (
		window.innerHeight ? window.innerHeight : 0,
		document.documentElement ? document.documentElement.clientHeight : 0,
		document.body ? document.body.clientHeight : 0
	);
}

function f_scrollTop() {
	return f_filterResults (
		window.pageYOffset ? window.pageYOffset : 0,
		document.documentElement ? document.documentElement.scrollTop : 0,
		document.body ? document.body.scrollTop : 0
	);
}
function f_filterResults(n_win, n_docel, n_body) {
	var n_result = n_win ? n_win : 0;
	if (n_docel && (!n_result || (n_result > n_docel)))
		n_result = n_docel;
	return n_body && (!n_result || (n_result > n_body)) ? n_body : n_result;
}