I use NoScript to selectively allow what Javascript to run. Unfortunately most sites pull in Javascript from all kinds of places, so this is not an on/off proposition, but can result in various degrees of brokenness.
Is there a good way for site authors to put up a warning when a required external Javascript file did not load?
There is the <noscript> tag, but that is only triggered when Javascript is completely unavailable. And NoScript tells me when there are blocked Javascript files, but it cannot tell if those are really required (e.g. all the tracking and social networking widgets can be suppressed just fine).
I noticed that Stackoverflow puts up a nice alert sheet when googleapis.com is unavailable. Every site should have that.
