Using Buttons

Example 1: making words appear.
A button can write something on the page.

Step 1.

On this page there is a section of the page with an ID of "Greeting".
It looks like this: 

                    <section id='Greeting'>
                    .........
                    </section>

Step 2.

The javascript code called by the button is: 


                function SayHello(){
                    Greeting.innerHTML = "Hello";
                }

Step 3.

Code the Button: 

                <button onclick='SayHello()'>Click Me!</button>
.........

Just for Fun

Try changing your code.
Change Greeting.innerHTML = "Hello";
to Greeting.innerHTML += "Hello ";