Combine task

Question

Here you can see for Loop, and two functions.
For Loop adds a number to the variable,
Function I adds two numbers together,
Function II makes 3 second delay. The idea is to create something that adds the number every 3 seconds and it is changed not written next to each other.

<script type="text/javascript">
var i = 4;
for (; i<=15;) {
document.write(i);
i++;
}
</script>
<script>
function myFunction(a, b){
return a + b;
}
var x = myFunction(8,1);
document.write(x);
</script>
<script>
function addNumber(){
alert("Hey");
}
setInterval(addNumber, 3000);
</script>

Answer 1

I use simple ststements, tell the broeser what to do step by step. Keep it simple keep it up.