JavaScript catch parameter already defined

Question

I\'m trying to understand why I\'m getting the following error, not how to work around it.

Passing the following code to JSLint or JSHint yields the er

Answer 1

Check this answer out: JSLint complaining about my try/catch

As has mentioned, try opens a new block-scope. See https://developer.mozilla.org/en/JavaScript/Reference/Scope_Cheatsheet

Indeed the top of the document explains that it's not all standard, but in ES5, section 12.14 the section on executing a catch block clearly defines MDC's description as standard:

No matter how control leaves the Block the LexicalEnvironment is always restored to its former state.