This section provides a tutorial example on how to use the array length to truncate and iterate over array elements.
As an object, an array has a special property called "length". You can use the object dot (.) operator
to retrieve the length value: "array_name.length".
The array length property can be used to truncate an array by setting the "length" property to a lower value.
The array length property is also useful when you want to iterate all elements of an array.
For example, iterating all elements of an array with a "for" loop can be done as:
for (var i = 0; i < array_name.length; i++) {
... array_name[i];
}
Here is a tutorial example JavaScript that shows you how to truncate and iterate array elements
with the "length" property:
<html>
<!-- Loop_Array_Elements.html
Copyright (c) 2008 by Dr. Herong Yang, http://www.herongyang.com/
-->
<head><title>Loop Array Elements</title></head>
<body>
<pre>
<script type="text/javascript">
// Creating an empty array
var even_numbers = new Array();
// Storing 20 elements in the array
for (var i=0; i<20; i++) {
even_numbers[i] = i*2;
}
// Truncating the array length to 10
even_numbers.length = 10;
// Iterating all 10 elements
document.write("First 10 even numbers: ");
for (var i=0; i<even_numbers.length; i++) {
document.write(even_numbers[i]+", ");
}
</script>
</pre>
</body>
</html>
The output of this sample JavaScript is:
First 10 even numbers: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18,
