how to do for loop in javascript 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: javascript for loop

for (var i; i < 10; i++) {
  
}

Example 3: javascript for loop

var i;
for (i = 0; i < 10 ; i++) {
  //do something
}

Example 4: for loop javascript

var listItem = [
        {name: 'myName1', gender: 'male'},
        {name: 'myName2', gender: 'female'},
        {name: 'myName3', gender: 'male'},
        {name: 'myName4', gender: 'female'},
      ]

    for (const iterator of listItem) {
        console.log(iterator.name+ ' and '+ iterator.gender);
    }