I have this code

input.addEventListener('input', function(e) {
   const num = Number(e.target.value)
   if ( 1 <= num && num <= 999) {
      e.target.value = num + '.000'
      const range = document.createRange()
      const sel = window.getSelection()
      range.setStart(this, e.target.value.length)
      sel.addRange(range)
   }
})

I want to when type value such as 65 input value will be 65.000, and cursor position will after number 5. In range.setStart(this, e.target.value.length) with the first parameter I don't know what textNode corresponding to input value. How can I do that? tks