JavaScript support

Yes (in the browser app settings you should be able turn off or on JavaScript/ECMAscript support), but it does not support the latest JavaScript language versions, nor can it handle fully the features required by modern JavaScript libraries such as jQuery.

Note that some web sites, when they redirect you to some error page claiming that you need to turn on JavaScript, have been poorly implemented, and they're really not checking whether your browser supports JavaScript or not, but, e.g., whether you're using IE, Firefox, Chrome, Safari or Opera, and then just redirect you to such an error page, if they don't recognized the browser.