function hideThisTR(tr_name) {
 if (document.layers) {
	document.layers[tr_name].display = "none";
 }
 else if (document.all) {
	document.all[tr_name].style.display = "none";
 }
 else if (document.getElementById) {
	document.getElementById(tr_name).style.display = "none";
 }
}

function showThisTR(tr_name) {
 if (document.layers) {
	document.layers[tr_name].display = "block";
 }
 else if (document.all) {
	document.all[tr_name].style.display = "block";
 }
 else if (document.getElementById) {
	document.getElementById(tr_name).style.display = "block";
 }
}

function toggleTR(tr_name) {
 //initHiddenTRs();
 if (document.layers) {
	current = (document.layers[tr_name].display == 'none') ? 'block' : 'none';
	document.layers[tr_name].display = current;
 }
 else if (document.all) {
	current = (document.all[tr_name].style.display == 'none') ? 'block' : 'none';
	document.all[tr_name].style.display = current;
 }
 else if (document.getElementById) {
	vista = (document.getElementById(tr_name).style.display == 'none') ? 'block' : 'none';
	document.getElementById(tr_name).style.display = vista;
 }
}