JS 实现 ajax 异步浏览器兼容问题

<td> <input type="button" value="订单详情" id="but<s:property value="#o.oid"/>" onclick="showDetail(<s:property value="#o.oid"/>)"/> <div id="div<s:property value="#o.oid"/>"></div>  </td> <script type="text/javascript"> function showDetail(oid){ var but = document.getElementById("but"+oid); var div1 = document.getElementById("div"+oid); if(but.value == "订单详情"){ // 1.创建异步对象 var xhr = createXmlHttp(); // 2.设置监听 xhr.onreadystatechange = function(){ if(xhr.readyState == 4){ if(xhr.status == 200){ div1.innerHTML = xhr.responseText; }} } // 3.打开连接 xhr.open("GET", "${pageContext.request.contextPath}/ adminOrder_findOrderItem.action?oid="+oid+"&time= "+new Date().getTime(),true); // 4.发送 xhr.send(null); but.value = "关闭"; }else{ div1.innerHTML = ""; but.value="订单详情"; } } function createXmlHttp(){ var xmlHttp; try{ // Firefox, Opera 8.0+, Safari xmlHttp=new XMLHttpRequest();  } catch (e){ try{// Internet Explorer xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");  } catch (e){ try{ xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); } catch (e){}  }  } return xmlHttp; } </script> // 根据订单的id查询订单项: public String findOrderItem(){ // 根据订单id查询订单项: List<OrderItem> list = orderService.findOrderItem(order.getOid());   // 显示到页面: ActionContext.getContext().getValueStack().set("list", list);   // 页面跳转 return "findOrderItem"; }  <table width="100%">  <s:iterator var="orderItem" value="list">  <tr>   <td><img width="40" height="45" src="${ pageContext.request.contextPath }/<s:property value="#orderItem.product.image"/>"></td>   <td><s:property value="#orderItem.product.pname"/></td>   <td><s:property value="#orderItem.count"/></td>   <td><s:property value="#orderItem.subtotal"/></td>  </tr>  </s:iterator> </table>