To clarify: The question is to halt the script execution completely for a certain amount of time, not to delay the execution of some piece of code, which wouild be a task for setTimeout or setInterval.
A clean implementation of sleep() is just not possible and also not desireable in JavaScript.
setTimout and setInterval do NOT halt the script execution like some people here seem top think. The just register a function to be run postponed. The rest of the script will continue running while the timeout/interval is waiting.
Due to the asynchronous nature of JavaScript, the only way to "block" any code execution would the very ugly and ABSOLUTELY NOT RECOMMENDED while loop that runs for a given amount of time.
Since JavaScript itself runs in one single thread (we're not talking about WebWorkers API here ...). This would stop any JS code from being run until that loop finishes. But thats really bad style ...
If your program can not work without something like sleep(), maybe you should rethink your approach.
