function display_div_by_id(id_div) {
	document.getElementById(id_div).style.display = '';
}
function hide_div_by_id(id_div) {
	document.getElementById(id_div).style.display = 'none';
}
function highlightElements(parentId, htmlTag, color1, color2) {
	var blocParent = document.getElementById(parentId); 
	var lesTags = blocParent.getElementsByTagName(htmlTag); 
	for (var i = 0; i < lesTags.length; i++) {
	    lesTags[i].style.background = color1;
	    lesTags[i].style.color = color2;
	}
}
function downlightElements(parentId, htmlTag, color1, color2) {
	var blocParent = document.getElementById(parentId); 
	var lesTags = blocParent.getElementsByTagName(htmlTag); 
	for (var i = 0; i < lesTags.length; i++) {
	    lesTags[i].style.background = color1;
	    lesTags[i].style.color = color2;
	}
}