function elem(v) { return(document.getElementById(v)); }
function elemS(v) { return(document.getElementById(v).style); }
function toggle(v) { elemS(v).display=(elemS(v).display=='block'?'none':'block'); }
function toggleDisplay(v) { elemS(v).display=(elemS(v).display=='block'?'none':'block'); }
function toggleVisibility(v) { elemS(v).visibilty=(elemS(v).visibilty=='visible'?'hidden':'visible'); }