Java Script Object vs Array

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript variable</h2>

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

<script>
var plane = {name : "MS",model : 2001,weight : "2250kg",color : "White"};
document.write(plane.name,"<br>");
document.write(plane.model);
</script>

</body>
</html>