JavaScript variables declare outside or inside loop?

In AS3 I believe you should initialise all variables outside loops for increased performance. Is this the case with JavaScript as well? Which is better / faster / best-practice?

var value = 0;

for (var i = 0; i < 100; i++)
{
    value = somearray[i];
}

or

for (var i = 0 ; i < 100; i++)
{
    var value = somearray[i];
}