Loop Performance

LoopPref

var array = [];
for (var i = 0; i < 100; i++) {
    array.push(i);
}

console.time('loop ++i');
for(var i = 0; i < array.length; ++i) {
    var a = array[i];
}
console.timeEnd('loop ++i');

console.time('loop i++');
for(var i = 0; i < array.length; ++i) {
    var a = array[i];
}
console.timeEnd('loop i++');

console.time('loop length var');
for(var i = 0, length = array.length; i < length; i++) {
    var a = array[i];
}
console.timeEnd('loop length var');

console.time('loop revrse');
for(var i = array.length-1; i > 0; i--) {
    var a = array[i];
}
console.timeEnd('loop revrse');