通过ajax发送表格吗？

I have following html code and I don't know how to send data (email) to php variables. Variable $_POST['email'] doesn't work after submit. Maybe post by ajax would work but I don't know how, can someone help me? Thanks.

 <div  id="newmember" class="form-1">
                            <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
                                <div class="modal-dialog">
                                <div class="modal-content">         
                                    <div class="modal-body">
                                        <div class="row">
                                            <div class="col-md-12 text-center">
                                                <div class="pop-up">                             
                                                    <div class="box-1">

                                                    </div>
                                                    <img src="img/6.png" class="center-block" alt="..">

                                                    <div class="form-search space40">
                                                        <form action="index.php" method="post">
                                                            <div class="input-group input-group-lg mtop-10">
                                                                <input type="text" name="email" class="form-control input-lg" placeholder="Your email">
                                                                <span class="input-group-btn">
                                                                    <input type="submit" name="send" class="btn btn-lg-sub model-btn"  data-target="#login" id="model11"  data-toggle="modal"  data-dismiss="modal"><i class="fa fa-paper-plane" aria-hidden="true"></i> &nbsp; SEND</button>
                                                                </span>
                                                            </div>
                                                        </form>
                                                    </div>
                                                    <div class="space30"></div>
                                                    <div>

                                                    </div>
                                                        <div class="space30"></div>

                                                </div>
                                            </div>
                                        </div>                       
                                    </div>                        
                                </div>                  
                                </div>
                            </div><!-- end become a member modal -->
                        </div> <!-- end Form -->
                        <!-- Modal Login -->
                         <div class="form-1" id="logingform">
                            <div class="modal fade" id="login" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
                                <div class="modal-dialog">
                                    <div class="modal-content">
                                        <div class="modal-content">                                                 
                                            <div class="row">
                                                <div class="col-md-12 text-center">
                                                    <div class="pop-up">

                                                        <div class="box-1">
                                                            <h3><i class="fa fa-check-square-o" aria-hidden="true"></i> &nbsp; SENT</h3>
                                                        </div>
                                                        <img src="img/6.png" class="center-block" alt="..">
                                                        <div class="space40"></div>
                                                        <h4>Thank you for email.</h4>
                                                        <div class="space60"></div>

                                                    </div>
                                                </div>
                                            </div>
                                        </div>

                                    </div>
                                </div>
                            </div>
                        </div>

An ajax call looks something like this.

$.ajax({
  url: "YOUR_URL_HERE",
  type: "POST",
  success: function(response){
    // Do something on success.
  }
});

You can put the above code in a function and call it like this and give it a url

function postRequest(url){
  $.ajax({
    url: url,
    type: "POST",
    success: function(response){
      // Do something on success.
    }
  });
}