jsp:未发布ajax填充的dropbox的值_Ajax_Jsp_Servlets

jsp:未发布ajax填充的dropbox的值

ajax jsp servlets

jsp:未发布ajax填充的dropbox的值,ajax,jsp,servlets,Ajax,Jsp,Servlets,检索用ajax填充的dropbox的值时出现问题。无论选择什么值，相关参数和值都不存在。我已经搜索了几天，但是没有找到这个问题的好答案，所以谢谢你的帮助。以下是jsp站点的代码： <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /> <script lan

检索用ajax填充的dropbox的值时出现问题。无论选择什么值，相关参数和值都不存在。我已经搜索了几天，但是没有找到这个问题的好答案，所以谢谢你的帮助。以下是jsp站点的代码：

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<script language="javascript" type="text/javascript">  
      var xmlHttp

      function showSockets(str){
          if (typeof XMLHttpRequest != "undefined"){
            xmlHttp= new XMLHttpRequest();
          }
          else if (window.ActiveXObject){
            xmlHttp= new ActiveXObject("Microsoft.XMLHTTP");
          }
          if (xmlHttp==null){
            alert("Browser does not support XMLHTTP Request")
            return;
          } 
          var url="sockets_abstract.jsp";
          url +="?room=" +str;
          xmlHttp.onreadystatechange = socketChange;
          xmlHttp.open("GET", url, true);
          xmlHttp.send(null);
      }

      function socketChange(){   
          if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){   
            document.getElementById("socket").innerHTML=xmlHttp.responseText   
          }   
      }  
</script>  

<title>AJAX abstract</title>
</head>
<body>
<table align="center">
<thead>
<tr><td colspan="2" class="heading">Test ajax:</td></tr>
</thead>
<tbody>
<form action="show_parameters.jsp" method="post" name="mainForm">
<tr> 
<td>Location*:</td>
<td>
    <select name="location" size="1" onchange="showSockets(this.value)">
        <option selected value="room1">room1</option>
        <option value="room2">room2</option>
        <option value="room3">room3</option>
    </select>
</td>
</tr>
<tr> 
<td>Socket*:</td><td>
      <div id="socket">  
      <select name="room_socket" onchange="getSocket(this.value)">
        <option value='-1'></option>
      </select>  
      </div> 
</td>
</tr>
<tr><td colspan="2"><hr width="80%"></hr></td></tr>
<input type="hidden" name="insert" value="true"/>
<tr><td colspan="2" align="right"><input style="width:100%"  type="submit" value="Check Parameters" /></td></tr>
</form>
</tbody>
</table>
</body>
</html>

因此，套接字dropbox被完全忽略。

感谢您的帮助。

表单标记不是

t正文

标记的有效子项。如果将表单标记移到表外，则效果良好

<form action="show_parameters.jsp" method="post" name="mainForm">
<table align="center">
<thead>
<tr><td colspan="2" class="heading">Test ajax:</td></tr>
</thead>
<tbody>

<tr> 
<td>Location*:</td>
<td>
    <select name="location" size="1" onchange="showSockets(this.value)">
        <option selected value="room1">room1</option>
        <option value="room2">room2</option>
        <option value="room3">room3</option>
    </select>
</td>
</tr>
<tr> 
<td>Socket*:</td><td>
      <div id="socket">  
      <select name="room_socket" onchange="getSocket(this.value)">
        <option value='-1'></option>
      </select>  
      </div> 
</td>
</tr>
<tr><td colspan="2"><hr width="80%"></hr></td></tr>
<input type="hidden" name="insert" value="true"/>
<tr><td colspan="2" align="right"><input style="width:100%"  type="submit" value="Check Parameters" /></td></tr>

</tbody>
</table>
</form>


测试ajax：
地点*：
1号房间
房间2
3号房间
插座*：

谢谢，很简单。

<%@page import="java.util.*" %>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
   "http://www.w3.org/TR/html4/loose.dtd"> 

<html> 
    <head> 
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
        <title>JSP display all parameters</title> 
    </head> 
    <body> 
        <% 
            Enumeration en = request.getParameterNames();
            while (en.hasMoreElements()) {
                String parameterName = (String) en.nextElement();
                String parameterValue = request.getParameter(parameterName);
                out.println(parameterName+":"+parameterValue+"<br />");
            }
        %> 
    </body> 
</html>

location:room3
insert:true

<form action="show_parameters.jsp" method="post" name="mainForm">
<table align="center">
<thead>
<tr><td colspan="2" class="heading">Test ajax:</td></tr>
</thead>
<tbody>

<tr> 
<td>Location*:</td>
<td>
    <select name="location" size="1" onchange="showSockets(this.value)">
        <option selected value="room1">room1</option>
        <option value="room2">room2</option>
        <option value="room3">room3</option>
    </select>
</td>
</tr>
<tr> 
<td>Socket*:</td><td>
      <div id="socket">  
      <select name="room_socket" onchange="getSocket(this.value)">
        <option value='-1'></option>
      </select>  
      </div> 
</td>
</tr>
<tr><td colspan="2"><hr width="80%"></hr></td></tr>
<input type="hidden" name="insert" value="true"/>
<tr><td colspan="2" align="right"><input style="width:100%"  type="submit" value="Check Parameters" /></td></tr>

</tbody>
</table>
</form>