var arr = [1, 2, 3];
    for (var i = 0; i < arr.length; i++) {
        console.log(arr[i]);
    }
    console.log("---------------------");

    for(var item of arr) {
        console.log(item);
    }

    console.log("---------------------");

    arr.forEach(function(item,index,self){
        console.log(item);
        console.log(index);
    })

    console.log("---------------------");

    arr.map(function(item,index,self){
        console.log(item);
        console.log(index);
    })