// JavaScript Document
// shows or hides an element
function toggleDisplay(blockName){
	var myElement = document.getElementById(blockName);
	if (myElement != null){
		if(myElement.style.display == ""){
			myElement.style.display = "none";
		} else {
			myElement.style.display = "";
		}
	} else {
		alert("Error: element id "+blockName+" not found.");
	}
}