JavaScript实际应用：简单二级联动菜单实现

<form name="frm">


<select name="s1" onChange="redirec(document.frm.s1.options.selectedIndex)">


<option selected>请选择</option>


<option value="1">脚本语言</option>


<option value="2">高级语言</option>


<option value="3">其他语言</option>


</select>




<select name="s2">


<option value="请选择" selected>请选择</option>


</select>


</form>






<script language="javascript">


//获取一级菜单长度


var select1_len = document.frm.s1.options.length;


var select2 = new Array(select1_len);




//把一级菜单都设为数组


for (i=0; i<select1_len; i++)




...{


select2[i] = new Array();


}




//定义基本选项


select2[0][0] = new Option("请选择", " ");




select2[1][0] = new Option("PHP", " ");


select2[1][1] = new Option("ASP", " ");


select2[1][2] = new Option("JSP", " ");




select2[2][0] = new Option("C/C++", " ");


select2[2][1] = new Option("Java", " ");


select2[2][2] = new Option("C#", " ");




select2[3][0] = new Option("Perl", " ");


select2[3][1] = new Option("Ruby", " ");


select2[3][2] = new Option("Python", " ");




//联动函数


function redirec(x)




...{


var temp = document.frm.s2;


for (i=0;i<select2[x].length;i++)




...{


temp.options[i]=new Option(select2[x][i].text,select2[x][i].value);


}


temp.options[0].selected=true;




}




</script>