The for...in loop is used to loop through an object's properties. Let’s see a for…in statement to loop through an array.
Example
You can try to run the following code to learn how to use the for…in statement to loop through an array −
Live Demo
<html>
<body>
<script>
var items = new Array('Hello', 'World');
var i = 0;
for (var i in items) {
document.write(items[i]);
}
</script>
</body>
</html>