var tick = new Image(); tick.src = "/worldservice/learningenglish/multimedia/london/images/tick.gif";
var cross = new Image(); cross.src = "/worldservice/learningenglish/multimedia/london/images/cross.gif";		
	
function Answer_Radio(answer,image){

	var number = eval("document.form.question" + image + ".length");
	var thing = null;
	var i = 0;
       
	while (i < number ) {
       	if (eval("document.form.question" + image + "[" + i + "].checked")==true){ 
		thing = eval("document.form.question" + image + "[" + i + "].value");
		}
		i++;
	}
       
	if (thing == null) { 
	alert("Please select an answer and try again!"); return; 
	}
	
   (thing == answer ) ? 
	document["image" + image].src = tick.src : document["image" + image].src = cross.src;

}

function popup(exerciseNumber){
	full_url = window.document.location.href;
	finish = full_url.indexOf("read") + 4;
	full_url = full_url.substring(0, finish);
	url = full_url + exerciseNumber + "_popup.html";
	mywin = window.open(url, 'popup', 'menubar=yes,toolbar=yes,scrollbars=yes,resizable=yes,width=400,height=450,top=25,left=25');
mywin.focus();
}	

function newWindow(url){
	popup = window.open(url, 'popup', 'scrollbars=yes,resizable=yes,width=400,height=450,top=25,left=25');
popup.focus();
}