JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="email" id="email" />
<input type="submit" name="asd" id="asd" />

JavaScript

$(function()
{
$("#email").change(function() {
var txt=$(this).val();
  

//var pattern = new RegExp(“a*bbbc”, “i”); // case-insensitive
var pattern = new RegExp("^[a-zA-Z0-9_\.\-]+@[a-zA-Z0-9\-]+\.[a-zA-Z0-9\-\.]+$");

var ckv = pattern.test(txt);
var txtMainColor=$(this).css("border-color");
if(!ckv)
{
$("input:submit").attr({"disabled":"disabled"});
$(this).css({"border-color":"red"});
}
else
{
$("input:submit").removeAttr("disabled");
$(this).css({"border-color":txtMainColor});
}

});
});