JavaScript increasing variable

Question

I want to add ID to each element of class .content, and I want each ID to have integer increase by 1. Example:

Answer 1

Use this in the each loop :

$(".content").each(function(index) { 
    this.id = 'content_' + index;
});

Otherwise you are selecting all the elements with class .content

JS only approach:

var content = document.querySelectorAll('.content');

[].forEach.call(content, function(item, index) {
  item.id = "content_" + (index+1);
});

ES6/ES2015 syntax:

let content = document.querySelectorAll('.content');

[].forEach.call(content, (item, index) => item.id = `content_${(index+1)}`);