how do i call a js method?

function runFunction() {
  myFunction();
}

function myFunction() {
  alert("runFunction made me run");
}

runFunction();<button onclick="sayHello()">say hello</button>  <script>    'use strict';  //force the context to be undefined    function sayHello() {      console.log(this);      console.log(arguments);      console.log('hello');    }  </script>