<!DOCTYPE html>
<html>
<body>

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

<script>
function employee(name, jobtitle, born) {
    this.name=name;
    this.jobtitle=jobtitle;
    this.born=born;
}
employee.prototype.salary = 2000;

var fred = new employee("Fred Flintstone", "Caveman", 1970);
document.getElementById("demo").innerHTML = fred.salary;
</script>

</body>
</html>