title: can't send jquery value to php code
body: <p>I tried to send a variable value from Jquery to php code,but it doesn't work although it appears successfully in console:</p>
  
  <p>Ajax:</p>
  
  <pre><code>$('#commission').change(function(){
      var coinval=$('select[name=cointype]').val();
      $.ajax({
          url: 'core_functions/parse_coins.php', //This is the current doc
          type: "POST",
          data: ({coinname: coinval}),
              success: function(data){
                  console.log(data); 
                  var recent_btc_price=&lt;?php show_btc_price(); ?&gt;; //10122.9
                  var com=$('#commission').val();
                  var com_amount_only=com * recent_btc_price /100;
                  var convert_comm_amount=Number(com_amount_only);
                  var totalpricewithcomm=recent_btc_price + convert_comm_amount;
                  var round_totalprice=totalpricewithcomm.toFixed(2);
                  $('#display').text("$"+round_totalprice);
              }
      });
  })
  </code></pre>
  
  <p>PHP:</p>
  
  <pre><code>if(isset($_POST['coinname'])){
      $coinname=$_POST['coinname'];
      echo $_POST['coinname'];
  }
  </code></pre>
  
  <p>HTML:</p>
  
  <pre><code>&lt;select name="cointype" id="deal_options" class="form-control"&gt;
      &lt;option value="bitcoin" &gt;Bitcoin (BTC)&lt;/option&gt;
      &lt;option value="ethereum"selected &gt;Ethereum (ETH)&lt;/option&gt;
  &lt;/select&gt;
  
  &lt;select class="form-control" id="commission"&gt;
      &lt;option value="0"&gt;0&lt;/option&gt;
      &lt;option value="1"&gt;1&lt;/option&gt;
      &lt;option value="2"&gt;2&lt;/option&gt;
      &lt;option value="3"&gt;3&lt;/option&gt;
      &lt;option value="4"&gt;4&lt;/option&gt;
      &lt;option value="5"&gt;5&lt;/option&gt;
      &lt;option value="6"&gt;6&lt;/option&gt;
      &lt;option value="7"&gt;7&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>why the data can't be handled by php?</p>