That covers it nicely. A couple of minor typos, though: You've got extraneous ")"s in the code-blocks under "Local Scope" and "A word of Caution", and I think

That covers it nicely. A couple of minor typos, though: You've got extraneous ")"s in the code-blocks under "Local Scope" and "A word of Caution", and I think the one under "very bad idea" needs the last line to be "})();" in place of just "});".