Viking777,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
</head>
<body>
<input name="" type="checkbox">
<input name="" type="checkbox">
<input name="" type="checkbox">
<script>
var inputs=document.querySelectorAll('[type="checkbox"]');
[].forEach.call(inputs, function(node) {
node.addEventListener("click", function() {
[].forEach.call(inputs, function(el) {
el.checked = el == node && el.checked
})
})
});
</script>
</body>
</html>