sfHover = function() {
	var sfEls = document.getElementById("menu").getElementsByTagName("LI");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
	    	this.className+=" sfhover";
		}

		sfEls[i].onmouseout=function() {
		this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}
	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);

function get_obj(obj_name) {
    return document.getElementById(obj_name);
}


function hide_all() {
/*
    document.getElementById("sportovni_arealy").style.display = "none"
    document.getElementById("rodinne_domy").style.display = "none"
*/
}
function switch_display(obj) {
    if (get_obj(obj).style.display == "inline") {
        hide_all();
        get_obj(obj).style.display = "none";
    } else {
        hide_all();
        get_obj(obj).style.display = "inline";
    }
}