The valueOf() method returns the primitive value of the object.
This method returns the array elements separated by commas.
If an array contains another array, the contents are flattened when this method is used.
<html>
<script language="JavaScript">
<!--
numbers = new Array(3,6,7);
colors = new Array("Blue","Green","Red",numbers);
document.write(colors.valueOf());
-->
</script>
</html>