The adding up button doesn't work in javascript

Question

I made a simple calculator in javascript but the + button doesn't work and it just show the numbers near together

Here is my code:

<script>
function calc(operator) {
    var x = document.getElementById("inp1").value;
    var y = document.getElementById("inp2").value;
    var z = 0;

    switch (operator) {
        case "+":
        z = x + y;
        break;
        case "-":
        z = x - y;
        break;
        case "*":
        z = x * y;
        break;
        case "/":
        z = x / y;
        break;
    }
    document.getElementById("result").innerHTML=z;
}
</script>

Answer 1

You may use like this:

z= +x + +y; // + is prefixed to convert input into number