Cycle setting

[meriah]

How can the sum of all values between the engines be deducted according to their number in the cycle?

e.g. 5 divAnd they need to be spied. Cycle, I think we need a number of blocks to change.

<div class="amount"> 1 </div>
<div class="amount"> 2 </div>
<div class="amount"> 3 </div>
<div class="amount"> 4 </div>
<div class="amount"> 5 </div>

js

window.onload = function(){
    var text = document.getElementsByClassName('amount');
    for (var i = 0 ; i < text.length; i++){
        sum = ++(text[i].innerHTML);      //тут не ясно 
      console.log(sum);
      }
}        

[baileigh]

In order to obtain one (the sum in this task), there is a remarkable method of mass https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce ♪

Okay. getElementsByClassName() It's not a mass, it's an object NodeList, it needs to be converted into a mass, and then applied. reduce() with a function that adds value to the " current " value from another inlet div'a.

The conversion of a massive object into a mass can be such a trick:

var myArray = Array.prototype.slice.call( massivoPodobnyObject)

As a result, the general code would look like:

function pluser(){
  var els = document.getElementsByClassName('amount');
  return Array.prototype.slice.call(els).reduce( addMe, 0);
}
function addMe(p,c,i,a){

// p - предыдущее значение общей суммы, c - очередной элемент массива

return p + parseInt(c.textContent);

}
window.onload = function(){

document.getElementById('total').innerHTML = '<div>Итого: ' + pluser() + '</div>';

}

<div class="amount"> 1 </div>

<div class="amount"> 2 </div>

<div class="amount"> 3 </div>

<div class="amount"> 4 </div>

<div class="amount"> 5 </div>

<div id="total"></div>