Just saw this on HN. Alexander Brevig : The //* /*/ //*/ comment toggle trick.
I’ve been using something very similar – the only difference between the last comment //*/ vs /**/
//*
someFunction();
/*/
someOtherFunction();
/**/
This technique is surprisingly “portable” – works in C++, Javascript, PHP, amongst others. And it works better than if (0) { someFunction(); } else { someOtherFunction(); } ‘cos syntax-highlighting works.
Another trick that I’ve used by abusing comments is to produce output that are both valid Javascript as well as HTML – at least to most browsers:
//<!--
alert("hello");
//-->
//<html><body>some text</body></html>
In Javascript context it’ll show a “hello” prompt, whereas in HTML context it’ll show “// //some text”. This can be used when say you’re returning a Javascript API and someone is misinterpreting it as HTML. You can of course be creative about the “some text” part. 🙂