JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post" id="BRV_brtrv" action="">

            <div data-role="fieldcontain">
                        <label for="BRV_brtrvrb">Requested By *</label>
                        <input type="text" name="BRV_brtrvrb" id="BRV_brtrvrb" value="<?php echo $_SESSION['name']; ?>" />
                </div>

            <div data-role="fieldcontain">
                <fieldset data-role="controlgroup" data-type="horizontal">
                    <legend>Service Type *</legend>
                    <input type="radio" name="BRV-id-service-type" id="BRV-brtrv-standard-service" value="standard" />
                    <label for="BRV-brtrv-standard-service">Standard</label>

                    <input type="radio" name="BRV-id-service-type" id="BRV-brtrv-rapid-service" value="rapid" />
                    <label for="BRV-brtrv-rapid-service">Rapid</label>
                </fieldset>
            </div>


            <div data-role="fieldcontain">

                        <label for="BRV-brtrv-department">Department *</label>
                        <select name="BRV-brtrv-department" id="BRV-brtrv-department" class="select" data-inline="true" data-native-menu="false">
                            <option>Choose Department</option>
                            <?php
                    while($row = mysql_fetch_array($BRVdept_result))
                    {
                    $value=$row['name'];

                    $caption=$row['name'];

                    echo "<option value=\"", $value, "\">", $caption, "</option>";
                    }
                    ?>
                        </select>

                </div>

                <div data-role="fieldcontain">

                        <label for="BRV-brtrv-address">Address *</label>
                        <select name="BRV-brtrv-address" id="BRV-brtrv-address" class="select" data-inline="true" data-native-menu="false">
                            <option>Choose Address</option>
                            <?php
   ...

JavaScript

//function to update box # from slider in BOX RETRIEVAL
$(function() {
  $("#BRVbrtrv_boxnumber").hide();
  $("#BRV-brtrv-submitDiv").hide();
  $("#BRV-brtrv-slider").live("change", function() {
    if($(this).val() > 0) {
      $("#BRVbrtrv_boxnumber").addClass("ui-input-text").show();
      $("#BRV-brtrv-submitDiv").show();
      $("#BRVbrtrv_boxnumber").empty();
      for(var i = 0;i < $(this).val();i++) {
        $("#BRVbrtrv_boxnumber").append('<div data-role="fieldcontain"><label for="BRVbrtrv_boxnumber" class="ui-input-text">Enter box ' + (i + 1) + ' number:</label><input type="text" name="BRVbrtrv_boxnumber['+i+']" id="BRVbrtrv_boxnumber['+i+']" class="BRVbrtrv_boxnumber ui-input-text ui-body-null ui-corner-all ui-shadow-inset ui-body-a" required="required" /></div>')
      }
    }else {
      $(this).val() == 0 && ($("#BRVbrtrv_boxnumber").hide(), $("#BRV-brtrv-submitDiv").hide())
    }
  })
});


// function to deal with box requests

$(function() {

 $("#BRV_brtrv").submit(function() {

   var send = $(this).serialize();

    $.ajax({
      type: "POST",
      url: "boxrtrvajax.php",
      cache: false,
      data: send,
      success: function (data) {

      if (data == 'No data'){

       $('#brtv-result').addClass("result_msg").html('Please fill in all fields');
      }
      else
      {
      $('#brtv-result').addClass("result_msg").html("You have successfully retrieved: "+data);
      $("#BRV_brtrv").get(0).reset();

      }
     },
     error:function (xhr, ajaxOptions, thrownError){
      jAlert('There was an exception thrown somewhere');
      alert(xhr.status);
      alert(thrownError);
     }
   });
   return false;
  });
});