Mine

<script>
var input = prompt("With a fr_CA locale, enter 0.5 to fail, 0,5 to succeed");
var test = 0.5;
if(input != null)
    test = parseFloat(input);
alert(eval("test == 0.5"));
if(test == 0.5)
    alert("Works!");
else
    alert("Pain!");
</script>