Here is some random calculator.
C
7
8
9
/
4
5
6
*
1
2
3
-
0
.
=
+
<script>
function append(value) {
document.getElementById("result").value += value;
}
function clear() {
document.getElementById("result").value = "";
}
function calculate() {
try {
document.getElementById("result").value =
eval(document.getElementById("result").value);
} catch (e) {
alert('Invalid calculation');
clear();
}
}
</script>