关于更改jquery函数的问题

Question

<table class="variations">
   <tr>
      <td>
          <select name="up_options">
             <option value="" selected>Select Value</option>
             <option value="a">A</option>
             <option value="b">B</option>
             <option value="c">C</option>
             <option value="d">D</option>
             <option value="e">E</option>
          </select>
      </td>
   </tr>
</table>

<script type="text/javascript">
    jQuery(document).ready(function() {
        jQuery('.variations select').change(function(){
           alert(jQuery('.single_variation').text());
        });
    });
</script>

<script type="text/javascript">
    jQuery(document).ready(function(e) {
        jQuery('.variations select').on('change', function(){
           alert(jQuery('.single_variation').text());
        });
    });
</script>

请帮帮我，我对此很困惑

Answer 1

原始代码没有什么“问题”，但您可以进行以下改进：

   // Shortcut for DOM ready with locally scoped $
   jQuery(function($) {

        // Delegated event handler attached to a common ancestor
        $('.variations').on('change','select',function(){

            // this is the select itself, so use its val()
           var currentSelectVal = $(this).val();

           // Do something with the selection
           $('.single_variation').text(currentSelectVal);
        });
    });

jsfiddle:http://jsfiddle.net/trueblueaussie/z9ev6rrp/2/

注意：我期待着看到页面的其余部分&代码，以便确定您的实际问题所在：）