Cycle-writing

[Kadyn]

I'll draw a line with the cycles. 1_1 2 3 4 5 2 2 3 4 5 3_1 2 3 4 5 Please find a mistake.

function t4() {
    let out = document.querySelector('.out-4');
    a = '';
    for (i = 1 ; i <=3;i++) {
        a += i + '_'
        for (k = 0; k <= 5 ; i++) {
            a += ' ';
        }
    }
    out.innerHTML = a;
}
document.querySelector('.b-4').onclick = t4;

[juvenalb]

function t4() {
  let a = '';
  for (let i = 1; i <= 3; i++) {
    a += i + '_'
    for (let k = 1; k <= 5; k++) {
      a += k + ' ';
    }
  }
  return a.trim();
}
console.log("[" + t4() + "]");