网页弹出警告框 'null'为空或不是对象
打开网页的时候就弹出警告框 'null'为空或不是对象，一天了也没有搞定，求帮助，以下是整个页面文件。用到的是DWR，兄弟姐妹们解救下小弟。再次感谢！
<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%><%@include file="../common/common.jsp" %><!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=GB18030"><link href="../style/oa.css" rel="stylesheet" type="text/css"><script language="javascript" src="../script/public.js"></script><script type="text/javascript" src="<%=request.getContextPath() %>/dwr/engine.js"></script><script type="text/javascript" src="<%=request.getContextPath() %>/dwr/util.js"></script><script type="text/javascript" src="<%=request.getContextPath() %>/dwr/interface/aclManager.js"></script><script type="text/javascript">//授权function addOrUpdatePermission(field){ dwr.engine.setAsync(false); //如果被选择上，则同时选择其"不继承"和"启用"checkbox if(field.checked){ $(field.moduleId+"_USE").checked = true; <c:if test="${aclInfo.principalType eq 'User' }"> $(field.moduleId+"_EXT").checked = true; addOrUpdateExtends(field); </c:if> } aclManager.addOrUpdatePermission( "${aclInfo.principalType}", ${aclInfo.principalId}, field.moduleId, field.permission, field.checked );}//设置用户的继承特性function addOrUpdateExtends(field){ aclManager.addOrUpdateUserExtends( ${aclInfo.principalId}, field.moduleId, !field.checked );}//点击启用checkboxfunction usePermission(field){ //如果checkbox被选中，意味着需要更新ACL的状态 //更新C/R/U/D以及Extends状态 //设置为同步方式，以便DWR依次发出下列请求 dwr.engine.setAsync(false); if(field.checked){ addOrUpdatePermission($(field.moduleId+"_C")); addOrUpdatePermission($(field.moduleId+"_R")); addOrUpdatePermission($(field.moduleId+"_U")); addOrUpdatePermission($(field.moduleId+"_D")); <c:if test="${aclInfo.principalType eq 'User' }"> addOrUpdateExtends($(field.moduleId+"_EXT")); </c:if> }else{ aclManager.delPermission( "${aclInfo.principalType}", ${aclInfo.principalId}, field.moduleId ); $(field.moduleId+"_C").checked = false; $(field.moduleId+"_R").checked = false; $(field.moduleId+"_U").checked = false; $(field.moduleId+"_D").checked = false; <c:if test="${aclInfo.principalType eq 'User' }"> $(field.moduleId+"_EXT").checked = false; </c:if> }}function initTable(){ aclManager.searchAclRecord( "${aclInfo.principalType}", ${aclInfo.principalId}, function(datas){ for(var i=0; i < datas.length; i++){ var moduleId = datas[i][0]; var cState = datas[i][1]; var rState = datas[i][2]; var uState = datas[i][3]; var dState = datas[i][4]; var extState = datas[i][5]; //alert(extState); $(moduleId+"_C").checked = cState == 0 ? false : true; alert($(moduleId+"_C").checked); $(moduleId+"_R").checked = rState == 0 ? false : true; $(moduleId+"_U").checked = uState == 0 ? false : true; $(moduleId+"_D").checked = dState == 0 ? false : true; <c:if test="${aclInfo.principalType eq 'User' }"> $(moduleId+"_EXT").checked = extState == 0 ? true : false; </c:if> $(moduleId+"_USE").checked = true; } } );}</script><c:choose> <c:when test="${aclInfo.principalType eq 'Role' }"> <c:set var="title" value="请给角色【${role.name }】授权"/> </c:when> <c:otherwise> <c:set var="title" value="请给用户【${user.person.name }】授权"/> </c:otherwise></c:choose><title>${title }</title></head><body onload="initTable()"><center><TABLE class="tableEdit" border="0" cellspacing="1" cellpadding="0" style="width:560px;"> <TBODY> <TR> <!-- 这里是添加、编辑界面的标题 --> <td align="center" class="tdEditTitle">${title }</TD> </TR> <TR> <td> <!-- 主输入域开始 --><table class="tableEdit" style="width:560px;" cellspacing="0" border="0" cellpadding="0"> <tr> <td class="tdEditLabel" >顶级模块</td> <td class="tdEditLabel">二级模块</td> <td class="tdEditLabel" >权限</td> <c:if test="${aclInfo.principalType eq 'User' }"> <td class="tdEditLabel" >不继承</td> </c:if> <td class="tdEditLabel" >启用</td> </tr> <!-- 输出模块树 --> <c:forEach items="${modules }" var="module"> <tr> <td>${module.name }</td> <td></td> <td> <input type="checkbox" id="${module.id }_C" onclick="addOrUpdatePermission(this)" moduleId="${module.id }" permission="0">C <input type="checkbox" id="${module.id }_R" onclick="addOrUpdatePermission(this)" moduleId="${module.id }" permission="1">R <input type="checkbox" id="${module.id }_U" onclick="addOrUpdatePermission(this)" moduleId="${module.id }" permission="2">U <input type="checkbox" id="${module.id }_D" onclick="addOrUpdatePermission(this)" moduleId="${module.id }" permission="3">D </td> <c:if test="${aclInfo.principalType eq 'User' }"> <td><input type="checkbox" id="${module.id }_EXT" onclick="addOrUpdateExtends(this)" moduleId="${module.id }"></td> </c:if> <td><input type="checkbox" id="${module.id }_USE" onclick="usePermission(this)" moduleId="${module.id }"></td> </tr> <c:forEach items="${module.children }" var="child"> <tr> <td></td> <td>${child.name }</td> <td> <input type="checkbox" id="${child.id }_C" onclick="addOrUpdatePermission(this)" moduleId="${child.id }" permission="0">C <input type="checkbox" id="${child.id }_R" onclick="addOrUpdatePermission(this)" moduleId="${child.id }" permission="1">R <input type="checkbox" id="${child.id }_U" onclick="addOrUpdatePermission(this)" moduleId="${child.id }" permission="2">U <input type="checkbox" id="${child.id }_D" onclick="addOrUpdatePermission(this)" moduleId="${child.id }" permission="3">D </td> <c:if test="${aclInfo.principalType eq 'User' }"> <td><input type="checkbox" id="${child.id }_EXT" onclick="addOrUpdateExtends(this)" moduleId="${child.id }"></td> </c:if> <td><input type="checkbox" id="${child.id }_USE" onclick="usePermission(this)" moduleId="${child.id }"></td> </tr> </c:forEach> </c:forEach></table> <!-- 主输入域结束 --> </td> </TR> </TBODY></TABLE><TABLE> <TR align="center"> <TD colspan="3" bgcolor="#EFF3F7"> <input type="button" class="MyButton" value="关闭窗口" onclick="window.close()"> </TD> </TR></TABLE></center></body></html>