For Loop Usage in Javascript

Itacen Sabacok | Mar 27, 2021 
1// The for statement creates a loop with 3 optional expressions:
2for (expression 1; expression 2; expression 3) {
3  // code block to be executed
4}
5
6for (var i = 0; i < 10; i++) {
7  text += "The number is " + i;
8}


Expression 1 is optional so it can be omitted.

1var i = 0;
2const num = [1, 2, 3, 4, 5]
3for (; i < num.length; i++) {
4  text += num[i] + "<br>";
5}


Expression 3 is optional so it can also be omitted.

1var i = 0;
2const num = [1, 2, 3, 4, 5]
3for (; i < len;) {
4  text += num[i] + "<br>";
5  i++;
6}

For Loop Usage in HTML

 1<!DOCTYPE html>
 2<html>
 3<body>
 4<h2>JavaScript for loop</h2>
 5<p id="demo"></p>
 6
 7<script>
 8  var i = 0;
 9  const num = [1, 2, 3, 4, 5]
10  for (; i < len;) {
11    text += num[i] + "<br>";
12    i++;
13  }
14  document.getElementById("demo").innerHTML = text;
15</script>
16
17</body>
18</html>