JSFiddle - React, Tailwind, and code Playground

HTML

<div id="res"></div>

JavaScript

function TestMAIL(email)
{
var re=/^[a-zA-Z0-9\-_]+[a-zA-Z0-9\.\-_]+@[a-zA-Z0-9\-_]+\.[a-zA-Z\.\-_]{1,}[a-zA-Z\-_]+/i;
return re.test(email)
}
tabmails=["truc@machin.com","kjkjmkj", 12321, "bidule.chouette@bazard-mundo.uk"]
;
$(function(){
    for (mail in tabmails){
        $("#res").append( $('<div/>').addClass('res').html(tabmails[mail] + "=>" +( TestMAIL(tabmails[mail])?"OK":"KO")))    
    }

    $('.res:contains("KO")').css('color','red')
})