Good morning, I'm trying the getElementById function in a document, but I have a problem with radio controls.
I'd like to get the radio control selected, but it always return me the first radio button and then the value London.
What's the right syntax?

Thanks in advance

My HTML is
<input type="radio" name="city" id="city" value="London">London
<input type="radio" name="city" id="city" value="Madrid">Madrid
<input type="radio" name="city" id="city" value="Milan" checked>Milan

and my Javascript
var city = document.getElementById("city");
alert(city.value);