JSFiddle - React, Tailwind, and code Playground

by Lokesh Yadav

HTML

<div id="box1">box</div>
<div id="box2">box</div>
<div id="box3">box</div>
<div id="box4">box</div>
<div id="box5">box</div>

CSS

.highlight { 
    color: red;
}

JavaScript

var substr = ['box1','box2']

// Plain JavaScript
for (var i = 0; i < substr.length; ++i) {
    document.getElementById(substr[i]).className = "highlight"
}

//For Each
substr.forEach(function(item) {
    $('#' + item).addClass('highlight')
});

//Generic loop:
for (var i = 0; i < substr.length; ++i) {
    $('#' + substr[i]).addClass('highlight')
}