While / For Loop Counting

JavaScript
1 
var parameter = process.argv.slice(2);
var m = Number(parameter[0]);
var n = Number(parameter[1]);

let sum = 0

function count() {
  for (let m = 0; m <= n;  m++ ) {
    sum += m
  }
  return sum;
}
console.log("Erste Zahl: " + m);
console.log("Zweite Zahl: " + n);
console.log(count("Die Summe ist: " + m, n));

var parameter = process.argv.slice(2);
var m = Number(parameter[0]);
var n = Number(parameter[1]);

let summe = 0;

function ceins(m, n) {
  while (m <= n) {
    summe = summe + m;
    m++;
  }
  return summe;
}
console.log(ceins(m, n));

Why does the While Loop work correctly with counting and the for loop not?
As an example the while loop solve 2 and 4 = 9 and the for loop 2 and 4 = 10
Thanks :slightly_smiling_face:

2

solved it with setting i = m

let sum = 0

function count() {
  for (i= m; i <= n;  i++ ) {
    sum += i
    console.log(sum)
  }
  return sum;
}