DOM对象的ajax应用实例详解

<script type="text/javascript" src="${pageContext.request.contextPath }/script/pub.js?1.1.11"></script>

/***
 * domId：表单Form2的名称
 * action：表示URL连接
 * sForm：表单Form1的名称 */Pub.submitActionWithForm=function(domId,action,sForm){  /**第一步：创建Ajax引擎对象*/
  var req = Pub.newXMLHttpRequest();  /**第二步：req.onreadystatechange表示事件处理函数（相当于一个监听），用来监听客户端与服务器端的连接状态*/
  var handlerFunction = Pub.getReadyStateHandler(req, domId,Pub.handleResponse);
  req.onreadystatechange = handlerFunction;  /**第三步：打开一个连接，要求：如果是POST请求，需要设置一个头部信息，否则此时不能使用req.send()方法向服务器发送数据*/
  req.open("POST", action, true);
  req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); 
  /**第四步：向服务器发送数据，格式：name=张三&age=28*/
  var str = Pub.getParams2Str(sForm); 
  //传递表单Form1中的元素作为参数给服务器  req.send(str);
}

/**
 * 用于创建ajax引擎 */Pub.newXMLHttpRequest=function newXMLHttpRequest() {  var xmlreq = false;  if (window.XMLHttpRequest) {xmlreq = new XMLHttpRequest();
  } else if (window.ActiveXObject) {     try {
      
      xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e1) {       
      try {
      
        xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e2) {
          
        alert(e2);
      }
    }
  }  return xmlreq;
}

/**
 * @Description:传递表单Form1中的元素作为参数
 * @param sForm：传递表单Form1的名称
 * @returns {String}：使用ajax返回服务器端的参数，传递的就是表单Form1中元素的参数 */Pub.getParams2Str=function getParams2Str(sForm){ var strDiv="";      
 try {var objForm=document.forms[sForm];  if (!objForm)return strDiv;  var elt,sName,sValue;  for (var fld = 0; fld < objForm.elements.length; fld++) {
      elt = objForm.elements[fld];    
      sName=elt.name;
      sValue=""+elt.value;      if(fld==objForm.elements.length-1)
          strDiv=strDiv + sName+"="+sValue+"";       else   
          strDiv=strDiv + sName+"="+sValue+"&";
   }


  }  catch (ex) {return strDiv;
    } 
   return strDiv;
}

=  (req.readyState == 4   (req.status == 200"HTTP error: "+

/**
 * @Description:将结果返回dictionaryEdit.jsp，并放置到dictionaryIndex.jsp的Form2中
 * @param data：服务器返回的结果
 * @param eleid：表单Form2的名称 */Pub.handleResponse= function handleResponse(data,eleid){      //获取表单Form2的对象  var ele =document.getElementById(eleid);      //将返回的结果放置到表单Form2的元素中  ele.innerHTML = data;
    
}

/**  
    * @Name: edit
    * @Description: 跳转到数据字典编辑页面
    * @Parameters: 无
    * @Return: String：跳转到system/dictionaryEdit.jsp*/public String edit(){//1.获取数据类型String keyword = elecSystemDDL.getKeyword();//2.使用数据类型查询数据字典，返回List<ElecSystemDDL>List<ElecSystemDDL> list=elecSystemDDLService.findSystemDDLListByKeyword(keyword);
        request.setAttribute("list", list);return "edit";
    }

List<ElecSystemDDL> findSystemDDLListByKeyword(String keyword);

/**  
    * @Name: findSystemDDLListByKeyword
    * @Description: 根据数据类型名称查询数据字典
    * @Parameters: keyword:数据类型名称
    * @Return: List：存储ElecSystemDDL对象集合*/@Overridepublic List<ElecSystemDDL> findSystemDDLListByKeyword(String keyword) {//查询条件String condition="";//查询条件对应的参数List<Object> paramsList = new ArrayList<Object>();if(StringUtils.isNotBlank(keyword)){
            condition=" and o.keyword=?";
            paramsList.add(keyword);
        }//传递可变参数Object[] params = paramsList.toArray();//排序Map<String, String> orderby = new  LinkedHashMap<String, String>();
        orderby.put("o.ddlCode", "asc");
        List<ElecSystemDDL> list = elecSystemDDLDao.findCollectionByConditionNoPage(condition, params, orderby);return list;
    }

<%@taglib uri="/struts-tags" prefix="s"%>

<s:if test="#request.list!=null && #request.list.size()>0">
                    <s:iterator value="#request.list">
                        <tr>
                           <td class="ta_01" align="center"  width="20%"><s:property value="ddlCode"/></td>
                           <td class="ta_01" align="center"  width="60%">
                                   <input id="<s:property value="ddlCode"/>" name="itemname" type="text" value="<s:property value="ddlName"/>"  size="45" maxlength="25"></td>
                           <td class="ta_01" align="center"  width="20%">
                                   <a href="#" onclick="delTableRow('<s:property value="ddlCode"/>')">
                            <img src="${pageContext.request.contextPath }/images/delete.gif" width="16" height="16" border="0" style="CURSOR:hand"></a>
                          </td>
                        </tr>
                    </s:iterator>
                </s:if>
                <s:else>
                    <tr>
                       <td class="ta_01" align="center"  width="20%">1</td>
                       <td class="ta_01" align="center"  width="60%">
                               <input name="itemname" type="text"  size="45" maxlength="25">
                       </td>
                       <td class="ta_01" align="center"  width="20%"></td>
                    </tr>
                </s:else>