addNumbers

https://www.reddit.com/r/javascript/comments/48muj4/cannot_set_property_innerhtml_of_null_error/#oo

by Adrian Mejias

HTML

<h2>addNumbers <small>(1, 2, 3, 4, 5)</small></h2>
<strong>Result:</strong> <span id="addFunction"></span>

CSS

h2 small {
  color: #777;
}

JavaScript

function addNumbers() {
  var sum = 0;
  for (var i = 0; i < arguments.length; i++) {
    sum += arguments[i];
  }
  return sum;
}
document.getElementById('addFunction').innerHTML = addNumbers(1, 2, 3, 4, 5);