javascript - Getting Optional input values from a form? -

i have modified bootstrap form own usage. email form collects name, email, phone & question inputs. user hits send button , emails information predetermined email address.

i'd have ability optionally capture user's phone number. i've removed required & data-validation-required-message tags , added name="phone".

right below inputs send email predetermined address if there phone number in phone input field... i'd send email regardless of phone number or not.

what overlooking?

html contact form :

<div class="col-xs-12"> <form name="sentmessage" id="contactform" novalidate> <div class="row control-group"> <div class="form-group col-xs-12 floating-label-form-group controls"> <label>name</label> <input type="text" class="form-control" placeholder="name" id="name" required data-validation-required-message="please enter name.">  <p class="help-block text-danger"></p>                                 </div>                             </div>                             <div class="row control-group">   <div class="form-group col-xs-12 floating-label-form-group controls">  <label>email address</label>   <input type="email" class="form-control" placeholder="email address" id="email" required data-validation-required-message="please enter email address.">    <p class="help-block text-danger"></p>    </div>    </div>  <div class="row control-group">    <div class="form-group col-xs-12 floating-label-form-group controls">     <label>phone number</label>     <input type="tel" class="form-control" placeholder="phone number" id="phone" name="phone">     <p class="help-block text-danger"></p>    </div>    </div>  <div class="row control-group">    <div class="form-group col-xs-12 floating-label-form-group controls">     <label>question? we've got answers!</label>     <textarea rows="5" class="form-control" placeholder="message" id="message" required data-validation-required-message="oops, tell what's on mind."></textarea>     <p class="help-block text-danger"></p>      </div>      </div>     <br>     <div id="success"></div>       <div class="row">      <div class="input-group">      <div class="form-group col-xs-6">      <button type="submit" class="btn btn-contact btn-sm hover">send</button> 

js :

$(function() {      $("input,textarea").jqbootstrapvalidation({         preventsubmit: true,         submiterror: function($form, event, errors) {             // additional error messages or events         },         submitsuccess: function($form, event) {             // prevent spam click , default submit behaviour             $("#btnsubmit").attr("disabled", true);             event.preventdefault();              // values form             var name = $("input#name").val();             var email = $("input#email").val();             var phone = $("input#phone").val();             var message = $("textarea#message").val();             var firstname = name; // success/failure message             // check white space in name success/fail message             if (firstname.indexof(' ') >= 0) {                 firstname = name.split(' ').slice(0, -1).join(' ');             }             $.ajax({                 url: "././mail/contact_me.php",                 type: "post",                 data: {                     name: name,                     phone: phone,                     email: email,                     message: message                 },                 cache: false,                 success: function() {                     // enable button & show success message                     $("#btnsubmit").attr("disabled", false);                     $('#success').html("<div class='alert alert-success'>");                     $('#success > .alert-success').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>&times;")                         .append("</button>");                     $('#success > .alert-success')                         .append("<strong>your message has been sent. </strong>");                     $('#success > .alert-success')                         .append('</div>');                      //clear fields                     $('#contactform').trigger("reset");                 },                 error: function() {                     // fail message                     $('#success').html("<div class='alert alert-danger'>");                     $('#success > .alert-danger').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>&times;")                         .append("</button>");                     $('#success > .alert-danger').append("<strong>sorry " + firstname + ", seems mail server not responding. please try again later!");                     $('#success > .alert-danger').append('</div>');                     //clear fields                     $('#contactform').trigger("reset");                 },             })         },         filter: function() {             return $(this).is(":visible");         },     });      $("a[data-toggle=\"tab\"]").click(function(e) {         e.preventdefault();         $(this).tab("show");     }); });  // when clicking on full hide fail/success boxes $('#name').focus(function() {     $('#success').html(''); }); 

php :

<?php // check empty fields if(empty($_post['name'])        ||    empty($_post['email'])       ||    empty($_post['phone'])       ||    empty($_post['message']) ||    !filter_var($_post['email'],filter_validate_email))    {     echo "no arguments provided!";     return false;    }  $name = $_post['name']; $email_address = $_post['email']; $phone = $_post['phone']; $message = $_post['message'];  // create email , send message $to = 'info@example.com';  $email_subject = "website contact form:  $name"; $email_body = "hey!! have received new message website contact form.\n\n"."here details:\n\nname: $name\n\nemail: $email_address\n\nphone: $phone\n\nmessage:\n$message"; $headers = "from: info@example.com\n";  $headers .= "reply-to: $email_address";  mail($to,$email_subject,$email_body,$headers); return true;             ?>