Using for loop to calculate a specific step of fibonacci with JavaScript

Question

I'm trying to make an alert which will tell you the n'th step of Fibonacci using a for loop. What I have so far is

var x=1;
var y=1;

var call = function(n) {
    if (n===1||2) {
          alert(1);
        }
    else {
    for(i=3; i<n+1; i++) {
          y=(x+y);
          x=y-x;
          if (i===n) {
            alert(y);
          }
      }
  }
};
call(prompt("Calculate Fibonacci to how many steps?"));

How I've tried to make it work is:

1. Set variable x and y to 1
2. Create a function named call which does the following:
3. Check if the number provided when the function is called is 1 or 2, if so alert 1 (1 being the first two steps of Fibonacci)
4. If n is not 1 or 2, start for loop at count=3
5. if count is less than one more than the called step run the following:
6. add x and y together
7. set y to this total
8. set x to the total, minus x
9. if the count is equal to the step called, alert with the total
10. add one to the count, go through loop again

But I'm always alerted with 1, even if I change the alert from the first if statement from 1 to a string. I'm not sure if there's an error in the code or in the logic of it.

I've seen a for loop isn't the most efficient way to do this, but I'd like to get it to work this way for learning's sake. I'm only a few lessons in Code Academy so my experience is very limited. Other pages that address this or a very similar problem are

Fibonacci calculator steps
http://ecomputernotes.com/js/javascript-tutorial/javascript-for-loop
https://answers.yahoo.com/question/index?qid=20091001160834AA5xiZ1

Answer 1

This

if (n===1||2) {

needs to be

if (n===1||n===2) {

Your code is evaluating the truthiness of 2, which is always true.

Also, it's unnecessary to evaluate i===n during each iteration. This will be true only after the last iteration of the loop, so just alert(y) after the loop.