JavaScript Closure

js_closure.js

function foo() {
	var res = [];
	for (var i = 0; i < 3; i++) {
		res.push(function() {
			document.write(i);
		});
	}
	return res;
}

var funcs = foo();
for (var i = 0; i < funcs.length; i++) {
	funcs[i]();
}

// prints:
// 333

I don't have clear explanation. Just, that 'var i' in for loop is bind to foo() and i in function(){...document.write(i)} is evaluated at the last value of i of the for loop.

By removing var in for loop it works as expected
... for (i = 0; i < 3; i++) { ....

But it makes i 'global scope' ...so like this, is it really still a closure ? Don't know... Javascript quirk ?