请教一个问题，我有三个下拉列表框，第二个显示的数据，要根据第一个点击的值来做为条件显示。

要向后台提交吗？如果你写在javabean里面的话，那么只能通过submit来传递参数。
如果不向后台提交的话，只能用javaSript实现。

进入页面时，先把数据存到多元数组里边（javascript），然后onChange第一个时调用javascript函数

如果你的页面加载没有非常多的动画(也就是说,如果你的页面加载不慢的话),那么,如下的方法是不错的:主题: 为了这个下拉框联动建立一个BEAN.(注:那个BEAN不是用来产生数据的,产生数据的BEAN,,如你所说,已经有了,新建立一个BEAN,专门用来管理显示的)假设: 你当前的页面是  A.JSP, 提交跳转不论, 下拉框的ONCHANGE跳转到下述的ATEMP.JSP文件
      新建立一个页面显示BEAN为:  APAGE.CLASS,
      新建立一个ATEMP.JSP, 在ATEMP.JSP中有: <JSP:USEBEAN CLASS=APAGE....>,这个文件加载后自动跳转到A.JSP.  选择第一个下拉框后,系统后台走了:  A.JSP--> ATEMP.JSP-->A.JSP
   第二个下拉框的显示内容由APAGE来控制, (APAGE用到的数据不自己产生, 它从SESSION里面取数据.按楼主说, 数据已经在SESSION里面的了)

这样看起来繁,已经是最简单的了,如果楼主用JAVASCRIPT来实现联动, 一定会吐血的(至于血是什么颜色的,比如黑色或者绿色,...不得而知)

用javascript的onChange比较快，在你的第一个select筐中加入onChange="你写的javascript的function"，在你的function中改变第二个select筐的值。

不是，就是在客户端，javaScript怎么实现呀。我想问一下，javaScript的变量能不能传到jsp中来。

如果你的每一个select筐，选项不多，都是固定的，那比较简单，要是都是从数据库中取出来的，那就需要提交再查库了！

用 JavaScript。
有很多论坛，在注册时填写省市的时候都是这么做的，比如“雷傲论坛”，它是把某个省的所有城市名称放在一个字符串中，中间用一个符号间隔，30几个省的数据放在一个数组中……然后 JavaScript 编写……或者看看俺的方法……
---------------------------------------------
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
</head><body>
<form name="form1" method="post" action="">
<p>
  <select name="select1" onChange="onOfficeSelectChange();">
  </select>
</p>
<p>
<select name="select2">
  </select>
</p>
</form>
<script language="JavaScript" type="text/JavaScript">function CLabelValue (label, value)
{
this.label = label;
this.value = value;
}function CSectionOffice (label, value, OfficeID)
{
this.label = label;
this.value = value;
this.officeID = OfficeID;
}var theOffices = new Array (3);
theOffices[0] = new CLabelValue ("ÂÞºþË°Îñ¾Ö", "001");
theOffices[1] = new CLabelValue ("¸£ÌïË°Îñ¾Ö", "002");
theOffices[2] = new CLabelValue ("Éß¿ÚË°Îñ¾Ö", "003");var theSectionOffices = new Array (10);
theSectionOffices[0] = new CSectionOffice ("ÂÞºþ¿ÆÊÒ1", "001", "001");
theSectionOffices[1] = new CSectionOffice ("ÂÞºþ¿ÆÊÒ2", "002", "001");
theSectionOffices[2] = new CSectionOffice ("ÂÞºþ¿ÆÊÒ3", "003", "001");theSectionOffices[3] = new CSectionOffice ("¸£Ìï¿ÆÊÒ1", "004", "002");
theSectionOffices[4] = new CSectionOffice ("¸£Ìï¿ÆÊÒ2", "005", "002");
//theSectionOffices[5] = new CSectionOffice ("¸£Ìï¿ÆÊÒ3", "006", "002");
theSectionOffices[5] = {label:"¸£Ìï¿ÆÊÒ3", value:"006", officeID:"002"};theSectionOffices[6] = new CSectionOffice ("Éß¿Ú¿ÆÊÒ1", "007", "003");
theSectionOffices[7] = new CSectionOffice ("Éß¿Ú¿ÆÊÒ2", "008", "003");
//theSectionOffices[8] = new CSectionOffice ("Éß¿Ú¿ÆÊÒ3", "009", "003");
theSectionOffices[8] = {label:"Éß¿Ú¿ÆÊÒ3", value:"009", officeID:"003"};
theSectionOffices[9] = new CSectionOffice ("Éß¿Ú¿ÆÊÒ4", "010", "003");
var aNewElement;
for (var i=0; i<theOffices.length; i++)
{
aNewElement = document.createElement("OPTION");
aNewElement.text = theOffices[i].label;
aNewElement.value = theOffices[i].value;document.all.select1.options.add (aNewElement);
}
function onOfficeSelectChange ()
{
var OfficeID = document.all.select1.value;
var aNewElement;
var i;//alert ("you choose: " + OfficeID); // clear old options...
for (i=document.all.select2.length-1; i>=0; i--)
document.all.select2.remove (i); // ¿ÉÒÔÂï£¿ // create new options...
for (i=0; i<theSectionOffices.length; i++)
{
if (theSectionOffices[i].officeID == OfficeID)
{
aNewElement = document.createElement("OPTION");
aNewElement.text = theSectionOffices[i].label;
aNewElement.value = theSectionOffices[i].value;
document.all.select2.options.add (aNewElement);
}
}
}</script></body>
</html>

机器有问题，从UltraEdit或者editPlus拷贝出来粘贴到记事本中是乱码……
-------------------------
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
</head><body>
<form name="form1" method="post" action="">
<p>
  <select name="select1" onChange="onOfficeSelectChange();" >
  </select>
</p>
<p>
<select name="select2">
  </select>
</p>
</form>
<script language="JavaScript" type="text/JavaScript">function CLabelValue (label, value)
{
this.label = label;
this.value = value;
}function CSectionOffice (label, value, OfficeID)
{
this.label = label;
this.value = value;
this.officeID = OfficeID;
}var theOffices = new Array (3);
theOffices[0] = new CLabelValue ("罗湖税务局", "001");
theOffices[1] = new CLabelValue ("福田税务局", "002");
theOffices[2] = new CLabelValue ("蛇口税务局", "003");var theSectionOffices = new Array (10);
theSectionOffices[0] = new CSectionOffice ("罗湖科室1", "001", "001");
theSectionOffices[1] = new CSectionOffice ("罗湖科室2", "002", "001");
theSectionOffices[2] = new CSectionOffice ("罗湖科室3", "003", "001");theSectionOffices[3] = new CSectionOffice ("福田科室1", "004", "002");
theSectionOffices[4] = new CSectionOffice ("福田科室2", "005", "002");
//theSectionOffices[5] = new CSectionOffice ("福田科室3", "006", "002");
theSectionOffices[5] = {label:"福田科室3", value:"006", officeID:"002"};theSectionOffices[6] = new CSectionOffice ("蛇口科室1", "007", "003");
theSectionOffices[7] = new CSectionOffice ("蛇口科室2", "008", "003");
//theSectionOffices[8] = new CSectionOffice ("蛇口科室3", "009", "003");
theSectionOffices[8] = {label:"蛇口科室3", value:"009", officeID:"003"};
theSectionOffices[9] = new CSectionOffice ("蛇口科室4", "010", "003");
var aNewElement;
for (var i=0; i<theOffices.length; i++)
{
aNewElement = document.createElement("OPTION");
aNewElement.text = theOffices[i].label;
aNewElement.value = theOffices[i].value;document.all.select1.options.add (aNewElement);
}
function onOfficeSelectChange ()
{
var OfficeID = document.all.select1.value;
var aNewElement;
var i;//alert ("you choose: " + OfficeID); // clear old options...
for (i=document.all.select2.length-1; i>=0; i--)
document.all.select2.remove (i); // 可以嘛？ // create new options...
for (i=0; i<theSectionOffices.length; i++)
{
if (theSectionOffices[i].officeID == OfficeID)
{
aNewElement = document.createElement("OPTION");
aNewElement.text = theSectionOffices[i].label;
aNewElement.value = theSectionOffices[i].value;
document.all.select2.options.add (aNewElement);
}
}
}</script></body>
</html>

单在客户端javaScript的变量是不能传递给jsp的。
同时，在客户端jsp只是在画面load的时候解析一次，生成静态的html，里面的java source都变成了固定条件下的固定值，无法再进行新的判断，新的操作。
所以如果想在客户端完成的话，首先在画面load的时候就要把jsp中的数据（多条）传递给javaScript数组，当画面触发了某些事件的时候，由javaScript来作处理。如果你想后台提交的话当我没说。

调试易

请教一个问题，我有三个下拉列表框，第二个显示的数据，要根据第一个点击的值来做为条件显示。

解决方案 »