function swap(targetId) {
    if (document.getElementById) {
    	var target = document.getElementById(targetId);
	            
	    var parent = target.parentNode;
	            
    	var divList = parent.getElementsByTagName("div");
	            
	    for (var i=0; i < divList.length; i++)
	        divList[i].style.display = "none";
	            
        if (target.style.display == "none") {
            target.style.display = "block";
	    }
	    else {
	        target.style.display = "none";
        }
    }
}