PHP-Ajax: Contact Form submit and email

// PHP
// Email Submit
if ( isset($_POST['email']) && isset($_POST['name']) && isset($_POST['text']) && filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) ) {
 
  // detect & prevent header injections
  $test = "/(content-type|bcc:|cc:|to:)/i";
  foreach ( $_POST as $key => $val ) {
    if ( preg_match( $test, $val ) ) {
      exit;
    }
  }
  
  // send email
  // replace YC email account with client account for production: [email protected]
  mail( "[email protected]", "Biagio Contact Form: ".$_POST['name'], $_POST['text'], "From:" . $_POST['email'] );
   
}

// JQUERY
// Contact Form
$("#contact_form").submit(function(e){
    e.preventDefault();
    var 
        name = $("input[name=name]").val(),
        email = $("input[name=email]").val(),
        text = $("textarea").val(),
        dataString = $(this).serialize();

    if (isValidEmail(email) && (name.length > 0) && (text.length > 0) ){
        $.ajax({
            type: "POST",
            url: "inc/contact.php",
            data: dataString,
            success: function(){
                console.log(dataString);
                $('#contact_form').hide('slow');
                $('.success').fadeIn(1000);
            }
        });
    } else{
        $("input, textarea").each(function() {
            var element = $(this);

            element.removeClass('error');

            if (element.val().length < 1) {
                element.addClass('error');
            }
        });

        if(!isValidEmail(email)) {
            $("input[name=email]").addClass('error');
        }
    }

    return false;
});

function isValidEmail(emailAddress) {
    var pattern = new RegExp(/^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$/i);
    return pattern.test(emailAddress);
};