ajax 返回值赋值给予页面上的 隐藏控件

Question

ajax 返回值（xmlHttp.responseText）已经取出来了。现在目的，把取到的值 赋值 给 页面上的 隐藏控件，也没报js错，就是 隐藏控件 赋值不上去。小弟新手上路，请大虾帮忙了

Answer 1

<script language="javascript" type="text/javascript">
                var xmlHttp = false; 
                function ajax_process()
                {
                    xmlHttp.open("get", "GetValue.ashx", true);
                    xmlHttp.onreadystatechange = ajax_sumbitemployment;
                    xmlHttp.send(null);
                    function ajax_sumbitemployment()
                    {
                        if (xmlHttp.readyState == 4)
                        {
                            if(xmlHttp.status==200)
                            { 
                                document.getElementById("lcrumb").value = xmlHttp.responseText;
                                alert(document.getElementById("lcrumb").value);
                            }
                        }
                    }
                }
                //创建Ajax对象
                function CreateXmlHttp()
                {
                    try { xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); }
                    catch (e) { try { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); }
                    catch (e) { try { xmlHttp = new XMLHttpRequest(); }
                    catch (e) { xmlHttp = false; }}}
                }
                function name_value()
                {
                    CreateXmlHttp();
                    ajax_process();
                }
            </script><input type="hidden" id="lcrumb" name="lcrumb" value=""/>

Answer 2

alert(document.getElementById("lcrumb").value);
这里弹出来测试都是有值的

Answer 3

我把隐藏给予第三变量，然后打印 都是有值的 。
<input type="hidden" id="lcrumb" name="lcrumb" value=""/>
var hidden_value = document.getElementById("lcrumb").value;
hidden_value = xmlHttp.responseText;
alert(hidden_value);这样子弹出框也是取到 值的 ，也应说现在的 hidden_value 已经赋值了吧,可是事实不是这样