var DHTML = (document.getElementById || document.all || document.layers);

function getObj(name){
	if (document.getElementById){    // DOM level 1 browsers: IE 5+, NN 6+
		this.obj = document.getElementById(name);
		this.style = document.getElementById(name).style;
	}
	else if (document.all){  // IE 4
		this.obj = document.all[name];
		this.style = document.all[name].style;
	}
	else if (document.layers)  { // NN 4
		this.obj = document.layers[name];
		this.style = document.layers[name];
	}
}

// this function makes the element visible
function showelem(elemId) {
	if (!DHTML){
		alert ('Sorry, your browser does not support this functionality');
		return;
	}

	var el = new getObj(elemId);
	el.style.visibility = 'visible';
}

// this function makes the image invisible
function hideelem(elemId) {
	if (!DHTML){
		alert ('Sorry, your browser does not support this functionality');
		return;
	}

	var el = new getObj(elemId);

	el.style.visibility = 'hidden';
}