Separating the JavaScript and non-JavaScript versions of a web page into two separate pages if far from the ideal way of handling accessibility since it means that you have to double up on your web pages. That option while it is easy to code is therefore only really appropriate where we need to supply a significantly different web page for those without JavaScript to that which we want to provide to those with JavaScript.
In most cases it will be far better for us to have just the one web page for all visitors and link the JavaScript into the page in such a way that the page will still work (although perhaps not as nicely) when the JavaScript code doesn’t get run. The ideal way of coding your web page so that it will work correctly for everyone is to write and test it first without the JavaScript.
This may mean that you have forms that need to be submitted for server side processing with the associated delays before displaying either an answer or an error message telling you that the input was invalid. It may also mean that you need to hard code default content into some parts of your page which all of your JavaScript disabled visitors will see in place of the more dynamic content that those with JavaScript will see. For example with a seasonal background script we can attach one of the four seasonal backgrounds to always display for those without JavaScript or alternatively we can select a completely different background that will not look out of place regardless of the time of year. Provided that the actual content doesn’t actually refer to the background our visitors will be completely unaware that they are seeing anything different from other visitors.
Modern JavaScript allows us to easily add to, delete from, and generally make whatever changes that we require to the web page content from JavaScript itself. The ideal way of setting up most web pages for maximum accessibility is therefore to provide the non JavaScript version in the HTML and then use JavaScript to update that content to show what we want it to when JavaScript is enabled.
