http://www.csdn.net/expert/topic/1046/1046706.xml?temp=.8381464<select id=oSel1 onchange=Chg()>
<option> CPU
<option> 硬盘
<option> 主板
</select>
<select id=oSel2>
</select><script>//二维数据表格(二维数组)
var Table2dim = new Array(
new Array("Intel PIII", "AMD Athlon", "Intel Celoron"),
new Array("IBM", "Westwood", "Quantum"),
new Array("Asus", "Gigabyte"),
null
);//Chg() 和 ChgOptions(i) 都是通用的,只要修改上面的 oSel1 的选项和 Table2dim 的内容即可
function Chg()
{
ChgOptions(document.all.oSel1.selectedIndex);
}
function ChgOptions(iSel1)
{
if ( 0 <= iSel1 && iSel1 < Table2dim.length )
{
var oSel2 = document.all.oSel2, i; //删除所有旧选项(不知道有没有不用循环的删除办法)
for ( i = oSel2.options.length; -- i >= 0; )
oSel2.options.remove(i); //创建新关联选项
var Table1dim = Table2dim[iSel1];
for ( i = 0; i < Table1dim.length; i ++ )
{
var o = document.createElement('<option>');
o.text = Table1dim[i];
oSel2.options.add(o);
}
}
}//初始化
ChgOptions(0);
</script>
<option> CPU
<option> 硬盘
<option> 主板
</select>
<select id=oSel2>
</select><script>//二维数据表格(二维数组)
var Table2dim = new Array(
new Array("Intel PIII", "AMD Athlon", "Intel Celoron"),
new Array("IBM", "Westwood", "Quantum"),
new Array("Asus", "Gigabyte"),
null
);//Chg() 和 ChgOptions(i) 都是通用的,只要修改上面的 oSel1 的选项和 Table2dim 的内容即可
function Chg()
{
ChgOptions(document.all.oSel1.selectedIndex);
}
function ChgOptions(iSel1)
{
if ( 0 <= iSel1 && iSel1 < Table2dim.length )
{
var oSel2 = document.all.oSel2, i; //删除所有旧选项(不知道有没有不用循环的删除办法)
for ( i = oSel2.options.length; -- i >= 0; )
oSel2.options.remove(i); //创建新关联选项
var Table1dim = Table2dim[iSel1];
for ( i = 0; i < Table1dim.length; i ++ )
{
var o = document.createElement('<option>');
o.text = Table1dim[i];
oSel2.options.add(o);
}
}
}//初始化
ChgOptions(0);
</script>
你看一看吧.那里的程序改一下就可以用了.你上面说的看不清怎么变所以没能给你改.不是说到了高一就是理吧.是不?呵呵.
<option>请选择年级</option>
<option value="1">高一</option>
<option value="2">高二</option>
<option value="3">高三</option>
</select>
<select size="1" name="cc" >
<option>请选择年级</option>
</select>
</form><script>
function test(){
with(document.all){
var len=cc.options.length;
for(i=len-1;i>=1;i--)
{
cc.options.remove(i);
}
switch(nianji.value){
case "1":
cc.options[1]=new Option("文科",1);
cc.options[2]=new Option("理科",2);
break;
case "2":
cc.options[1]=new Option("asf",3);
break;
}
}
}
</script>
至于后台嘛,用mysql两数据表实现