Good question: I take it you are referring to the code below. The reason str is garbage collected is because of the modern implementation of the JS compiler in Chrome. Such modern JS compilers look specifically for such unused variables in closures, even when the variable is in the execution context of the closure.

To clarify, it is Chrome's decision to garbage collect the str variable in that context that resulted in str being garbage collected. It is not a result of a JavaScript bug.

Moreover, different browsers have different implementations for how they garbage collect variables in closures' scope chain. Heck, browsers do their own thing when it comes to many aspects of JavaScript.

On second thought (from our previous back and forth), you are correct that I did not explicitly discuss this specific issue in my earlier post. So you win :) and I have up-voted your two comments accordingly.

Here is the code I think you are referring to: var run = function () { var str = new Array(1000000).join('*'); var logIt = function () { console.log('interval'); }; setInterval(logIt, 100); }; setInterval(run, 1000);