JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="email" name="email" size="35" placeholder="Your email"/>
              <span id="err1_email" class="hidden" style="color: red">
                
                <br />
                Please fill this field.
              </span>
              <span id="err2_email" class="hidden" style="color: red">
                
                <br />
                Please enter a valid email.
              </span>
            </div>
            <div>
              <input type="text" id="email_confirm" name="email_confirm" size="35" placeholder="Confirm your email"/>
              <span id="err1_confirmemail" class="hidden" style="color: red">
                
                <br />
                Please fill this field.
              </span>
              <span id="err2_confirmemail" class="hidden" style="color: red">
                
                <br />
                Emails are not the same.
              </span>
            </div>

CSS

.hidden{
	display: none
}

JavaScript

$("#email").blur(function ()
    {
        if ($("#email").val() == "")
        {
            $("#err1_email").removeClass("hidden");
            $("#err2_email").addClass("hidden");
        }
        else
        {
            $("#err1_email").addClass("hidden");
            if (!emailregex.test($('#email').val()))
            {
                $("#err2_email").removeClass("hidden");
            }
            else
            {
                $("#err2_email").addClass("hidden");
            }
        }
    })
$("#email_confirm").blur(function ()
	    {
	        if ($("#email_confirm").val() == "")
	        {
	            $("#err1_confirmemail").removeClass("hidden");
	        }
	        else
	        {
	            $("#err1_confirmemail").addClass("hidden");
	            if ($("email_confirm").val().toLowerCase() != $("email").val().toLowerCase())
	            {
	                $("#err2_confirmemail").removeClass("hidden");
	            }
	            else
	            {
	                $("#err2_confirmemail").addClass("hidden");
	            }
	        }
    	})