Javascript: closure of loop?

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One solution, if you’re coding for a browser that uses JavaScript 1.7 or higher, is to use the let keyword:

for(var i = 0; i < 10; ++i) {
    let index = i;
    createButton(x, y, function() { alert("button " + index + " pressed"); }
}

From the MDC Doc Center:

The let keyword causes the item
variable to be created with block
level scope, causing a new reference
to be created for each iteration of
the for loop. This means that a
separate variable is captured for each
closure, solving the problem caused by
the shared environment.

Check out the MDC Doc Center for the traditional approach (creating another closure).

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