Question

我在表单中有一个隐藏字段，其值由javascript设置。我已确认该值确实已设定。但是，当我尝试将其发送到servlet时，它会生成一个空值。我使用POST方法提交给servlet并使用＆＃34; submit＆＃34;按钮。该值是通过＆＃34; qtyText＆＃34;中的用户输入获得的。文本框。在JS中，它的值被动态设置。为什么不将它发送到servlet？ JS

   function(calculateTotalPrice(txtbxvalue, price)
  {
   myForm = document.forms[0];        
      var txtBx = myForm.elements['qtyText'];
      var txtBxHidden = myForm.elements['qtyTextHidden'];
      for(var i = 0; i < txtBx.length; i++) 
         {
          var curTxtBx = txtBx[i].value; 
          var txtBxHiddenBx = txtBxHidden[i];
           txtBxHiddenBx.value = curTxtBx;
         }
   }

HTML

<table>

   <c:forEach items="${ListInServlet}" var= "exBean">
  <form name = "tableForm" method = "post" action= "/rpsapp/someservlet">
    <input type="hidden" name="productId" value= "<c:out Value 
                                          = "${exBean.productId}"/>"  />
         <input type="hidden"  value = "somevalue" name="qtyTextHidden"/>
         <input name = "qtyText" type = "textbox" size = "2" value = "" onChange 
                              = "calculateTotalPrice(this, '${exBean.price}')"/>

   </c:forEach>
  </form>
</table>

Answer 1

您的foreach语句（标记）与表单标记重叠。

您需要具有以下格式：

<c:forEach ...> <form ...> ... </form> </c:forEach>

Answer 2

您必须创建与产品一样多的隐藏变量。

  <form name = "tableForm" method = "post" action= "/rpsapp/someservlet">
   <c:forEach items="${ListInServlet}" var= "exBean">
    <input type="hidden" name="productId${exBean.productId}" value= "<c:out Value 
                                          = "${exBean.productId}"/>"  />
         <input type="hidden"  value = "somevalue" name="qtyTextHidden${exBean.productId}"/>
         <input name = "qtyText${exBean.productId}" type = "textbox" size = "2" value = "" onChange 
                              = "calculateTotalPrice(this, '${exBean.price}')"/>

   </c:forEach>
  </form>

JSP隐藏字段在servlet中生成null

2 个答案: