Alternating Table Rows With JavaScript And jQuery

One of the most popular stories on this website is on Alternating Table Rows With Template Toolkit And CSS. The example I use is how to stripe alternate rows in an HTML table by applying a seperate class to each row.

As I’ve been learning jQuery lately, I thought I’d update this example to show how to do it using this excellent JavaScript framework.

Firstly, we need to setup our styles. We’ll have a lite and a dark class to use that will just set a different background colour.

<style type="text/css">
.lite {background-color: #ddffff;}
.dark {background-color: #aaffff;}

We’ll also need an example table.

<table class="stripe">

Notice how I have given the table a class of stripe. This is important, I’m going to use jQuery to only select table elements that have this class name, else every table on the page would be striped.

The jQuery to achieve the striping is actually very simple.

<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function() {

Firstly we added the jQuery library to the page. Next we setup our striping code to only run once the DOM is place. This is important as we’re going to be selecting and manipulating over the DOM next. The next two lines apply the lite class to even table rows and the dark class to odd table rows. Let’s look at this in a bit more detail.

The selector $('table.stripe>tbody>tr:even') is easier to explain backwards. We look for even matching tr elements, that have a parent of tbody, that has a parent of table with a class of stripe. The use of the > symbol instead of just a space is to make sure the elements are direct parent and child elements instead of just ancestor and descendant. Why is this important? Well if we used a space any nested tables that happened to have an striped ancestor would also be striped. This isn’t normally what we’d want to happen.