make a for loop auto populate on open javascript w3schools code example

Example 1: javascript for loop

var colors=["red","blue","green"];
for (let i = 0; i < colors.length; i++) { 
  console.log(colors[i]);
}

Example 2: js for loop

var i; //defines i
for (i = 0; i < 5; i++) { //starts loop
  console.log("The Number Is: " + i); //What ever you want
}; //ends loop
//Or:
console.log("The Number Is: " + 0);
console.log("The Number Is: " + 1);
console.log("The Number Is: " + 2);
console.log("The Number Is: " + 3);
console.log("The Number Is: " + 4);
//They do the same thing!
//Hope I helped!