JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="message"></textarea>
<button type="button">Check</button>

JavaScript

$('button').click(function() {
    var value = $('#message').val();
    var error = ''
    var success = true;
    if (value == '' || value == 'Fill out this form and include an email or phone number to be contacted ...') {
        error = 'A message along with your contact details are required before sending.';
        success = false;
    }
    else if (value.search(/(\s|^)[a-zA-Z0-9_\.\-]+\@([a-zA-Z0-9\-]+\.)+[a-zA-Z0-9]{2,4}(\s|$)/) == -1 && value.search(/(\s|^)(?:\([2-9]\d{2}\)\ ?|[2-9]\d{2}(?:\-?|\ ?))[2-9]\d{2}[- ]?\d{4}(\s|$)/) == -1) {
        error = 'Your message should contain an email address or phone number.';
        success = false;
    }
    if (success) {
        alert('Success!');
    } else {
        alert(error);
    }
});