// function to toggle a <div> between visible and hidden

function toggle_visibility(divId) {
	
	// for newer browsers
	if (document.getElementById) {
		
		// get current display state
		var currDisp = document.getElementById(divId).style.display;
		
		// get current visibility state
		var currVis = document.getElementById(divId).style.visibility;

		// if the div has display set instead of visibility, toggle display attribute
		if (currDisp != '') {
			
			// if displayed, hide it
			if (currDisp == 'block') {
				document.getElementById(divId).style.display = 'none';
			
			// if not displayed, display it
			} else {
				document.getElementById(divId).style.display = 'block';
			}
		}
		
		// if the div has visibility set instead of display, toggle visibility attribute
		else if (currVis != '') {

			// if visible, hide it
			if (currVis == 'visible') {
				document.getElementById(divId).style.visibility = 'hidden';
			
			// if hidden, make it visible
			} else {
				document.getElementById(divId).style.visibility = 'visible';
			}
		}

	// for older type browsers
	} else if (document.all) {

		// get current display state
		var currDisp = document.all[divId].style.display;
		
		// get current visibility state
		var currVis = document.all[divId].style.visibility;

		// if the div has display set instead of visibility, toggle display attribute
		if (currDisp != '') {
		
			// if visible, hide it
			if (currDisp == 'block') {
				document.all[divId].style.display = 'none';
			
			// if hidden, make it visible
			} else {
				document.all[divId].style.display = 'block';
			}
		}

		// if the div has visibility set instead of display, toggle visibility attribute
		else if (currVis != '') {

			// if visible, hide it
			if (currVis == 'visible') {
				document.all[divId].style.visibility = 'hidden';
			
			// if hidden, make it visible
			} else {
				document.all[divId].style.visibility = 'visible';
			}
		}
	}
}