Unexpected token for loop

JavaScript
1

I use this:

for (i =1; i<10; i+=) {
    myArray.push(i);
}

and I get an error that won’t allow my code to run
) is an “unexpected token”, why?

pasting this works:

for (var i = 1; i < 10; i += 2) {
  myArray.push(i);
}
2

nevermind, I forgot the 2 and the var declaration