Question

This question is a follow up question for this question.

If some browsers download JS files even though the user has JS disabled, would it make sense to include JS files using JS to ensure the user isn’t forced to download the JS unnecessarily?

For example:

function inc(filename){
    var body = document.getElementsByTagName('body').item(0);
    script = document.createElement('script');
    script.src = filename;
    script.type = 'text/javascript';
    body.appendChild(script);
}

I found the above code here.

Are there any downsides to this code? I haven’t tested it yet to make sure it works properly, but it seems pretty straightforward.

I’m trying to avoid having multiple HTTP requests plus the download footprint of the code forced upon users that clearly don’t want it.

Also, how would this work if the user enabled JS after initially loading the site?

Does this even matter? Is it worth being concerned over?

Answer 1

I’m going to step back to this question:

Does this even matter? Is it worth being concerned over?

No, it’s not 🙂 The percentage of users who have JavaScript disabled should be very much the minority (in the majority of cases), it’s really not worth it to mess with the loading of all users to save a few HTTP requests (which should be cached) for a few, stay with <script> tags.

Also, look at the accepted answer in the previous question, in the initial testing 3/4 browsers don’t download it already, so really this is only for Chrome (and possibly IE), the other browsers already save the requests here.

Update: I just tested in IE8, it does not download any included JavaScript when it’s disabled, I’m not setup to test any other versions at the moment, but this is true in IE8 at least.