Why isn't this working? Javascript, text inputs' values and using them in an if statement

I think I'm missing something stupidly simple but can't figure out why this isn't working. I'm trying to use 4 values from 4 text inputs and activate an alert when the values = the string value stated.

<div id="AnswersFriends">
    <input type="text" align="center" id="TextFriend1" oninput="checkchange">
    <input type="text" align="center" id="TextFriend2" oninput="checkchange">
    <input type="text" align="center" id="TextFriend3" oninput="checkchange">
    <input type="text" align="center" id="TextFriend4" oninput="checkchange">
</div>
<script type="text/javascript"> 

function checkchange(){
var Ans1 = document.getElementsByID('TextFriend1').value;
var Ans2 = document.getElementsByID('TextFriend2').value;
var Ans3 = document.getElementsByID('TextFriend3').value;
var Ans4 = document.getElementsByID('TextFriend4').value;

if(Ans1=="Joe" && Ans2=="Joe" && Ans3=="Hugo" && Ans4=="Nathan") {
    alert("WellDone"); 
}
}
</script>