function displayOff(nr){
	document.getElementById(nr).style.display = 'none';
}
function displayOn(nr){
	document.getElementById(nr).style.display = 'block';
}

// the following method inverts the current mode
// i.e. turns displayed to hidden and vice-versa
function displayToggle(hiding_object,focus_field){
document.getElementById(hiding_object).style.display = (document.getElementById(hiding_object).style.display == 'none') ? 'block' : 'none';

/*focuses on the requested field (can only be used if link that ran it contains no anchor):
if(focus_field){
	document.getElementById(focus_field).contentWindow.focus(); 
}
*/
}