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copied!<p>This is indeed a major difference between C/C++ and JavaScript: JavaScript is a reference-counted, garbage-collected language, which means that objects can be reclaimed by the engine when they no longer have any references to them. The function you assign to <code>printColor</code> isn't on the stack, per se, as it would be in C or C++; it's allocated dynamically and then assigned to a variable outside your current scope. So, when control flow returns from <code>changeColor</code>, the anonymous function still has a reference count of <strong>1</strong> since the outer <code>printColor</code> refers to it, and thus it's usable from the outer scope.</p> <p>So, your example isn't so much of a scoping issue--it's clear that you declare <code>printColor</code> <em>outside</em> of the function scope of <code>changeColor</code>. When you define <code>changeColor</code>, it <a href="http://en.wikipedia.org/wiki/Closure_%28computer_science%29" rel="nofollow">closes</a> the upvalue <code>printColor</code> into the new function scope, making it accessible. Like <strong>Combat</strong> said, if you add a <code>var</code> to the second, inner definition of <code>printColor</code>, it'll <a href="http://en.wikipedia.org/wiki/Variable_shadowing" rel="nofollow"><em>shadow</em></a> the first <code>printColor</code> you declared and it won't be accessible outside that function block.</p> <p>As far as other issues to be aware of, yes, there are quite a few, but see my comment on your original post for a good start.</p>

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