JSFiddle - React, Tailwind, and code Playground

by webwakko

HTML

<input name="user1" value="bla1">
<input name="user2" value="bla2">
<input name="user3" value="bla1">
<input name="user4" value="bla4 bla1">
<input name="user5" value="bla5">

CSS

.red {background: red}

JavaScript

var inputs = $('input');

inputs.filter(function(i,el){
    return inputs.not(this).filter(function() {
        return this.value === el.value;
    }).length !== 0;
}).addClass('red');