return value from javascript function

function num(x, y) {
	var sum = x + y;
	return sum;
}<script>
function showName() {
  var result;
  result = addString('Hello', ' World');
  document.write (result );
}

// in below we will check how to return string from function
function addString(fName, lName) {
  var val;
  val = fName + lName;
  return val;  // returning string from function
}
</script>
<input type = "button" onclick = "showName()" value = "Result">
  
/*
I hope it will help you.
Namaste
Stay Home Stay Safe
*/function test(arg){
    return arg;
}