window.onload=function() {  
	document.getElementById("log").style.display="none";
	document.getElementById("reg").style.display="none";
	
	var radios = document.forms[0].elements["choose_action"]; 
	for (var i = [0]; i < radios.length; i++) 
		radios[i].onclick=displayLoginOptions; 
}

function displayLoginOptions() { 
	if (this.value == "1") { 
		document.getElementById("log").style.display="block"; 
		document.getElementById("reg").style.display="none"; 
	} else {
		document.getElementById("log").style.display="none"; 
		document.getElementById("reg").style.display="block"; 
	} 
}