Good morning I am using PHP for form validation it works on Desktop versions but not iOS what is the easiest way to fix this?

<span class="required_field">*</span><em>Required field</em>

<form action="/support_ticket.php" class="new_support_ticket" id="new_support_ticket" method="post" onSubmit="return checkForm(this); return false;"> <div style="margin:0;padding:0;display:inline"> <input name="authenticity_token" type="hidden" value="xxxxxxxxx=" /></div> <p> </p> <p> <label for="Your_first_name">First Name<span class="required_field"></span></label> <input id="first_name" name="first_name" size="30" type="text" required /> </p> <p> <label for="Your_last_name">Last Name<span class="required_field"></span></label> <input id="last_name" name="last_name" size="30" type="text" required /> </p> <p> <label for="Your_email__we_will_use_this_to_contact_you_">Your email<span class="required_field"></span>
</label> <input id="from_email" name="from_email" size="30" type="text" required /> </p> <!--<p> <label for="Your_phone_number">Your phone number</label> <input id="phone" name="phone" size="30" type="text" /></p> <p> <label for="Specify_the_nature_of_the_problem">Specify the nature of the inquiry<span class="required_field"></span></label> <select required id="nature_of_error" name="nature_of_error" tabindex="0" > <option value="">Reason...</option> <option value="1">Technical Support</option> <option value="2">Order pictures</option> <option value="3">Other Question- Current User</option> <option value="4">Refund</option>

</select> </p> <div style="width: 100%;"> <label for="Briefly_describe_your_problem">What's your Question? *</label> <textarea cols="30" id="text" name="text" rows="5" required="1" ></textarea> </div>

<p><input type="checkbox" name="chkFAQ" id="chkFAQ" value="unchecked" required="1" /> I have read the <a href="/faq.php" target="blank">Frequently Asked Questions Page</a> and I still need help.</p>

<?php $qls->Security->math_captcha(); ?>

<div class='form_clear'> <br /> <input id="support_ticket_submit" name="commit" type="submit" value="Support" /> </form>

</div>