Load KaTeX asynchronously using script async

[aterenin]

KaTeX seems to work out of the box with script async. If there are no major drawbacks from using this, I suggest adding it to the README.

[kevinbarabash]

I can't see why it wouldn't work with script async. The async attribute only affects when the script is loaded, right?

[aterenin]

I believe so. I tested it with the latest alpha version (beta version 404s because it has yet to propagate across the CDN), and it seems to just work. I also tested loading the CSS asynchronously by adding the following to the auto-render code.

var link = document.createElement("link");
link.rel = "stylesheet";
link.href = "https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-alpha2/katex.min.css";
link.integrity = "sha384-exe4Ak6B0EoJI0ogGxjJ8rn+RN3ftPnEQrGwX59KTCl5ybGzvHGKjhPKk/KC3abb" ;
link.crossorigin="anonymous";
document.getElementsByTagName("head")[0].appendChild(link);

I had to use the load event instead of DOMContentLoaded because it happens later, but other than that, everything seems to just work.

[edemaine]

Having an async example sounds cool. Calling autorender or whatever upon load event sounds perfect.

[kevinbarabash]

@aterenin if you have some time, would you mind adding a note in the README.md?

[aterenin]

The code I have above is, for whatever reason, not reliable - have noticed on my own site that it occasionally fails to load the style sheet.

I've thus reverted back to what is in README.md but if I end up figuring out what to change to make it work consistently I'll document everything.

[TruePath]

Maybe consider this technique? That's a nice way for those of us who are preprocessing the math on the server to load the css.