JSFiddle - React, Tailwind, and code Playground

HTML

<input value="111"> //similar
<input value="222">
<input value="111"> //similar
<input value="333">

JavaScript

var collection = $('input');
    var duplicates = $.map(collection, function(item){
        val = $(item).val();
        return ($('input[value="' + val + '"]').length > 1) ? val : null;
    });

    if(duplicates.length > 0) alert('There are similar values');