Javascript how do sum class numeric value?

Question

my question is class have number value how do fix this???

<span class="simpleCart_grandTotal"></span>
<p id="demo"></p>

<script>
var x = $('.simpleCart_grandTotal').text();
var y = 2;
var z = x * y;
document.getElementById("demo").innerHTML = z;
</script>

the output <span class="simpleCart_grandTotal"></span> is $10 this multiplied by 2 result will show <p id="demo"></p> is $20 and how do use this $ sign remove from first class and put second class??

Answer 1

var x = $('.simpleCart_grandTotal').text();

var intX = Number(x.replace(/[^0-9.]+/g,""));

var y = 2;

var z = "$" + (intX * y);

document.getElementById("demo").innerHTML = z;