js 三级关联菜单效果实例

代码如下:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312" />
<title>js 三级关联菜单</title>
</head>
<body>
<FORM name="isc">
<select name="example" size="1" onChange="redirect(this.options.selectedIndex)">
<option selected>---Select1----</option>
<option>Webmaster Sites</option>
<option>News Sites</option>
</select>
<select name="stage2" size="1" onChange="redirect1(this.options.selectedIndex)">
<option value=" " selected> </option>
<option value=" " selected>---Select2-----</option>
<option value=" " selected>---Select2-----</option>
</select>
<select name="stage3" size="1" onChange="redirect2(this.options.selectedIndex)">
<option value=" " selected> </option>
<option value=" " selected>---Select3-----</option>
<option value=" " selected>---Select3-----</option>
</select>
<script>
var groups=document.isc.example.options.length
var group=new Array(groups)
for (I=0; I<groups; I++)
group[I]=new Array()
group[0][0]=new Option("---Select2---"," ");
group[1][0]=new Option("Now Select This One"," ");
group[1][1]=new Option("JavaScript","47");
group[1][2]=new Option("DHTML","46");
group[1][3]=new Option("CGI","45");
group[2][0]=new Option("Now Select This One"," ");
group[2][1]=new Option("General News","115");
group[2][2]=new Option("Technology News","116");
var temp=document.isc.stage2
function redirect(x){
for (m=temp.options.length-1;m>0;m--)
temp.options[m]=null
for (I=0;I<group[x].length;I++){
temp.options[I]=new Option(group[x][I].text,group[x][I].value)
}
temp.options[0].selected=true
redirect1(0)
}
var secondGroups=document.isc.stage2.options.length
var secondGroup=new Array(groups)
for (I=0; I<groups; I++) {
secondGroup[I]=new Array(group[I].length)
for (j=0; j<group[I].length; j++) {
secondGroup[I][j]=new Array() }}
secondGroup[0][0][0]=new Option("---Select 3---"," ");
secondGroup[1][0][0]=new Option("---Select 3---"," ");
secondGroup[1][1][0]=new Option("Now Select This One"," ");
secondGroup[1][1][1]=new Option("Website Abstraction","http://wsabstract");
secondGroup[1][1][2]=new Option("JavaScript for the non programmer","http://webteacher/javascript/");
secondGroup[1][1][3]=new Option("Java-Scripts.net","http://www.jb51.net");
secondGroup[1][2][0]=new Option("Now Select This One"," ");
secondGroup[1][2][1]=new Option("Dynamic Drive","dynamicdrive");
secondGroup[1][2][2]=new Option("Beginner's Guide to DHTML","geocities/ResearchTriangle/Facility/4490/");
secondGroup[1][2][3]=new Option("Web Coder","http://sc.jb51.net/");
secondGroup[1][3][0]=new Option("Now Select This One"," ");
secondGroup[1][3][1]=new Option("CGI Resources","cgi-resources");
secondGroup[1][3][2]=new Option("Ada's Intro to CGI","http://play.jb51.net/");
secondGroup[2][0][0]=new Option("---Select 3---"," ");
secondGroup[2][1][0]=new Option("Now Select This One"," ");
secondGroup[2][1][1]=new Option("CNN","cnn");
secondGroup[2][1][2]=new Option("MSNBC","msnbc");
secondGroup[2][1][3]=new Option("ABC News","abcnews");
secondGroup[2][2][0]=new Option("Now Select A Page"," ");
secondGroup[2][2][1]=new Option("News","news");
secondGroup[2][2][2]=new Option("Wired","wired");
var temp1=document.isc.stage3
function redirect1(y){
for (m=temp1.options.length-1;m>0;m--)
temp1.options[m]=null
for (I=0;I<secondGroup[document.isc.example.options.selectedIndex][y].length;I++){
temp1.options[I]=new Option(secondGroup[document.isc.example.options.selectedIndex][y][I].text,secondGroup[document.isc.example.options.selectedIndex][y][I].value)
}
temp1.options[0].selected=true
}
function redirect2(z){
window.location=temp1[z].value
}

//-->
</script>
</FORM>
</body>
</html></td>
   </tr>
 </table>