Should I inject style tags into the head dynamically or include include style tags in the body?

Question

I have some html content that gets embedded into a page via a server side call. So, when the page's html is being compiled on the server, a call is made to another server to return some html, which is then embedded within a div somewhere in the body. The problem is, this content contains it's own css. So, I wrote a script to inject style tags into the HEAD on ready, which works fine on desktop browsers. However, on mobile devices there's a fairly significant flash of unstyled content. I know that you're technically not supposed to include style tags in the body, but in this case would it yield better results to just include them in the body instead of injecting them into the head?

Answer 1

Some discussion here. In my experience a lot of enterprise content does it. Does that mean it's the RIGHT thing to do? I dont know. But it's certainly not frowned upon in my experience.

Source: https://www.w3.org/wiki/The_web_standards_model_-_HTML_CSS_and_JavaScript

Why separate?

Efficiency of code: The larger your files are, the longer they will take to download, and the more they will cost some people to view (some people still pay for downloads by the megabyte.) You therefore don’t want to waste your bandwidth on large pages cluttered up with styling and layout information in every HTML file. A much better alternative is to make the HTML files stripped down and neat, and include the styling and layout information just once in a separate CSS file. To see an actual case of this in action, check out the A List Apart Slashdot rewrite article where the author took a very popular web site and re-wrote it in XHTML/CSS.

Ease of maintenance: Following on from the last point, if your styling and layout information is only specified in one place, it means you only have to make updates in one place if you want to change your site’s appearance. Would you prefer to update this information on every page of your site? I didn’t think so.

Accessibility: Web users who are visually impaired can use a piece of software known as a “screen reader” to access the information through sound rather than sight — it literally reads the page out to them, and it can do a much better job of helping people to find their way around your web page if it has a proper semantic structure, such as headings and paragraphs. In addition keyboard controls on web pages (important for those with mobility impairments that can't use a mouse) work much better if they are built using best practices. As a final example, screen readers can’t access text locked away in images, and find some uses of JavaScript confusing. Make sure that your critical content is available to everyone.

Device compatibility: Because your HTML/XHTML page is just plain markup, with no style information, it can be reformatted for different devices with vastly differing attributes (eg screen size) by simply applying an alternative style sheet — you can do this in a few different ways (look at the [mobile articles on dev.opera.com] for resources on this). CSS also natively allows you to specify different style sheets for different presentation methods/media types (eg viewing on the screen, printing out, viewing on a mobile device.) Web crawlers/search engines: Chances are you will want your pages to be easy to find by searching on Google, or other search engines. A search engine uses a “crawler”, which is a specialized piece of software, to read through your pages. If that crawler has trouble finding the content of your pages, or mis-interprets what’s important because you haven’t defined headings as headings and so on, then your rankings in relevant search results will probably suffer.

It’s just good practice: This is a bit of a “because I said so” reason, but talk to any professional standards-aware web developer or designer, and they’ll tell you that separating content, style, and behaviour is the best way to develop a web application.

Additional stackoverflow articles:

Using <style> tags in the <body> with other HTML

Will it be a wrong idea to have <style> in <body>?

Answer 2

In this case, it sounds like the right solution is to fix up your architecture so that the server-side compiler can include CSS for the remote page in the page head. This probably involves separating the CSS of the remote page(s) out of the markup there and then grabbing it as a separate file to be included in the page head during compilation.

Since the right solution is not always feasible given a myriad reasons, compromise is often required. Leaving the CSS in the remote markup, if it produces the result you desire, could be the best solution for you. Or perhaps some other hack to get the CSS into the head server-side could be appropriate. You need to decide if it is worth the effort to do any of these things, if they are possible for you to accomplish given your constraints.