JSFiddle - React, Tailwind, and code Playground

HTML

<input id="email" type="text"/>

<button id="testEmail" onClick="CheckEmail(document.getElementById('email').value)">Check Email</button>

<div id="output">

</div>

JavaScript

function ValidateEmailAddress(emailString) {
  var emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
	return !!emailString && typeof emailString === 'string'
		&& emailString.match(emailRegex);
}

function CheckEmail(emailString)
{
   //get result as true/false
   var Result= ValidateEmailAddress(emailString);
	
	 if(Result)
	 {
	     document.getElementById("output").innerHTML="Valid Email Id";
   }
	 else
	 {
		document.getElementById("output").innerHTML="NOT a Valid Email Id";
	 }
}