- Not all search engines can handle JavaScript, Google is leading the way, but not perfect.
- Those NoScript users could be potential clients or users of your site. I love it when my conversation rate goes up 1%, and that becomes harder when you ignore 1-5% of users.
- Screenreaders generally do not support JavaScript [not true, see comment]. If only one blind user gets to access the content/design I created, then that is worth it to me. I am thinking as front-end engineer here, not as a business owner, where time is money. (Also depending on jurisdiction it may be against the law to be inaccessible).
- Noscript users will likely bounce in large numbers when seeing just a blank page. Simply adding a <noscript> tag, explaining why you need JavaScript goes a long way.
As a front-end engineer I go for maximum content accessibility. I don't meddle into the politics of things ("If we don't drop IE6 support, the web won't move forward!").
I totally understand the new landscape, where a lot of people have JavaScript on. Some web apps can not use progressive enhancement, because the JavaScript is core to the app. But for "static" content websites like these, it is certainly possible to make a website that is usable by most users, human and robot.
Please stop saying that. It hasn't been true for a good 5 years or so.
* http://www.brucelawson.co.uk/2011/javascript-and-screenreade...
* http://webaim.org/projects/screenreadersurvey4/#javascript
"WAI-ARIA addresses these accessibility challenges by defining how information about this functionality can be provided to assistive technology. With WAI-ARIA, an advanced Web application can be made accessible and usable to people with disabilities."
As mentioned elsewhere, screen readers fully support Javascript and have for a very long time (which you've updated your post to acknowledge). That was one of the big reasons I used to ensure sites worked without Javascript years ago.
NoScript users know enough to turn it on for a site for it to work. NoScript users only make up 0.08% of internet users worldwide, a far cry form 1-5%. Basically, you can safely give them a significantly reduced site experience or just a message to turn Javascript on. They're not really worth the effort in most cases. Hardly anyone disables JavaScript anymore as most sites simply won't work right without it.
If you want to expend the extra effort, more power to you. It's just that for most sites nowadays, it's not worth the time/money anymore.
Look at it this way, this __escaped_fragment__ is only supported by Google. No other search engine supports it. And considering that building it with progressive enhancement first, and then enhancing it with JavaScript, you get content that's indexable by any search engine, not just Google.
The workload is the same, the complexity is the same, the only difference is the focus on progressive enhancement first rather than try to bolt a clearly less optimal solution later.
Well, javascript support in w3m and lynx is still pretty poor. It makes it harder to easily get some content from offline reading using wget/curl.
It does depend on what kind of site/app you're making. I'd say that if your main content is text, then requiring js makes no sense (especially if you're publishing some blog posts on configuring server software -- I might want do download that article to a headless server).
I think most apps also benefit from an old school REST architecture, so that it is possible to eg: script your todo-app with curl to create a new todo-item without having to go through 3 pages of api-specs.
But that is exactly what you are doing anyways, you are just limiting it to googlebot for no reason.