有两个下拉框,在一个下拉框里选择一个项目,另一个下拉框里的选项会改变;请问用JS怎么实现?? http://lucky.myrice.com/javascriptexam/radioforselect.htmlhttp://lucky.myrice.com/javascriptexam/add_del_Select.htm 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 <html> <script> function change(){ for (var i=a.options.length;i>=0;i--) { b.options.remove(i); } switch(a[a.selectedIndex].innerText){ case "a1": oOption = document.createElement("OPTION"); b.options.add(oOption); oOption.innerText = "a11"; oOption = document.createElement("OPTION"); b.options.add(oOption); oOption.innerText = "a12"; break; case "a2": oOption = document.createElement("OPTION"); b.options.add(oOption); oOption.innerText = "a21"; oOption = document.createElement("OPTION"); b.options.add(oOption); oOption.innerText = "a22"; break; } } </script> <body> <select name="a" onchange="change()"> <option selected>a1 <option>a2 </select> <select name="b" onchange="change()"> <option selected>a12 <option>a12 </select> </body></html>oOption 的各种属性还能用函数改。你就自己捉摸吧 <html><head><script>function check(){ if(f1.d1.options[0].selected) { f1.d2.length=0 f1.d2.options.add(new Option("白菜","白菜")) f1.d2.options.add(new Option("萝卜","萝卜")) } else if(f1.d1.options[1].selected) { f1.d2.length=0 f1.d2.options.add(new Option("苹果","苹果")) f1.d2.options.add(new Option("桃","桃")) }}</script></head><body><form name="f1" method="POST" action="--WEBBOT-SELF--"> <p><select size="1" name="d1" onchange="check()"> <option>蔬菜</option> <option>水果</option> </select><select size="1" name="d2"> </select></p></form></body></html> function change() { for (var i=document.all.two.options.length;i>=0;i--) { document.all.two.options.remove(i); } switch (document.all.one.value) { case "1":var oOption = document.createElement("OPTION"); document.all.two.options.add(oOption); oOption.innerText = "One One"; oOption.value = "One One";break; case "2":var oOption = document.createElement("OPTION"); document.all.two.options.add(oOption); oOption.innerText = "Two Two "; oOption.value = "Two Two ";break; }} ...<select name="one" size=1 onChange="change();"><option value="1">1</option><option value="2">2</option></select><select name="two" size=1 ></select> 请看本版的专题:http://www.csdn.net/Subject/237/index.shtm function populatemxhweb(inForm,selected) {var selectedArray = eval(selected + "Array");while (selectedArray.length < inForm.mxhweb.options.length) {inForm.mxhweb.options[(inForm.mxhweb.options.length - 1)] = null;}for (var i=0; i < selectedArray.length; i++) {eval("inForm.mxhweb.options[i]=" + "new Option" + selectedArray[i]);}if ( navigator.appName == 'Netscape') {if (parseInt(navigator.appVersion) < 4) {window.history.go(0);}}中var selectedArray = eval(selected + "Array"); 不太懂eval是做什么的 如何理解jquery中的offset 怎么强制用户输入的是整数 动态图像显示问题 怎么能够限定checkbox只能选取固定个数 求一个过滤标签内容的正则表达式. javascript的小问题:关于return false 和 return true的 ff支持表格的添加删除行吗? 给<td>添加事件 一个innerHTML问题,请大家帮忙看一下!! 如何实现点击鼠标后打开一个新窗口,并关闭原先的窗口 一个比较棘手的问题!帮忙解决!在线等! Vml+Js算法:完成5个小球在网页运动(碰壁返回)的游戏,详细注释
<script>
function change(){
for (var i=a.options.length;i>=0;i--) {
b.options.remove(i);
}
switch(a[a.selectedIndex].innerText){
case "a1":
oOption = document.createElement("OPTION");
b.options.add(oOption);
oOption.innerText = "a11";
oOption = document.createElement("OPTION");
b.options.add(oOption);
oOption.innerText = "a12";
break;
case "a2":
oOption = document.createElement("OPTION");
b.options.add(oOption);
oOption.innerText = "a21";
oOption = document.createElement("OPTION");
b.options.add(oOption);
oOption.innerText = "a22";
break;
}
}
</script>
<body>
<select name="a" onchange="change()">
<option selected>a1
<option>a2
</select>
<select name="b" onchange="change()">
<option selected>a12
<option>a12
</select>
</body>
</html>oOption 的各种属性还能用函数改。你就自己捉摸吧
function check()
{
if(f1.d1.options[0].selected)
{
f1.d2.length=0 f1.d2.options.add(new Option("白菜","白菜"))
f1.d2.options.add(new Option("萝卜","萝卜"))
}
else if(f1.d1.options[1].selected)
{
f1.d2.length=0
f1.d2.options.add(new Option("苹果","苹果"))
f1.d2.options.add(new Option("桃","桃")) }}
</script>
</head><body><form name="f1" method="POST" action="--WEBBOT-SELF--">
<p><select size="1" name="d1" onchange="check()">
<option>蔬菜</option>
<option>水果</option>
</select><select size="1" name="d2">
</select></p>
</form></body></html>
for (var i=document.all.two.options.length;i>=0;i--) {
document.all.two.options.remove(i);
} switch (document.all.one.value) {
case "1":var oOption = document.createElement("OPTION");
document.all.two.options.add(oOption);
oOption.innerText = "One One";
oOption.value = "One One";break;
case "2":var oOption = document.createElement("OPTION");
document.all.two.options.add(oOption);
oOption.innerText = "Two Two ";
oOption.value = "Two Two ";break;
}
}
.
.
.
<select name="one" size=1 onChange="change();">
<option value="1">1</option>
<option value="2">2</option>
</select>
<select name="two" size=1 >
</select>
http://www.csdn.net/Subject/237/index.shtm
var selectedArray = eval(selected + "Array");
while (selectedArray.length < inForm.mxhweb.options.length) {
inForm.mxhweb.options[(inForm.mxhweb.options.length - 1)] = null;
}
for (var i=0; i < selectedArray.length; i++) {
eval("inForm.mxhweb.options[i]=" + "new Option" + selectedArray[i]);
}if ( navigator.appName == 'Netscape') {
if (parseInt(navigator.appVersion) < 4) {
window.history.go(0);
}}中var selectedArray = eval(selected + "Array"); 不太懂eval是做什么的