Tryit Editor v2.7

Edit This Code:
<!DOCTYPE html>
<html>
<body>

<p>
If you assign a value to a variable that has not been declared,
it will automatically become a GLOBAL variable:
</p>

<p id="demo"></p>

<script>
myFunction();
document.getElementById("demo").innerHTML =
"I can display " + carName;

function myFunction() {
    carName = "Volvo";
}
</script>

</body>
</html>