JavaScript实现二级联动

    //获取一级菜单长度    var select1_len = document.gpsiForm.brand.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");    //别克车型    select2[1][0] = new Option("英朗");    select2[1][1] = new Option("威朗");    select2[1][2] = new Option("昂科拉");    select2[1][3] = new Option("昂科威");    select2[1][4] = new Option("君威");    select2[1][5] = new Option("君越");    select2[1][6] = new Option("GL8");    select2[1][7] = new Option("昂科雷");    //福特车型    select2[2][0] = new Option("蒙欧迪");    select2[2][1] = new Option("福克斯");    select2[2][2] = new Option("猛禽");    select2[2][3] = new Option("锐界");    select2[2][4] = new Option("福睿斯");    select2[2][5] = new Option("金牛座");    select2[2][6] = new Option("翼搏");    select2[2][7] = new Option("翼虎");    select2[2][8] = new Option("野马");    select2[2][9] = new Option("探险者");    select2[2][10] = new Option("撼路者");    //雪佛兰车型     select2[3][0] = new Option("新科鲁兹");    select2[3][1] = new Option("科帕奇");    select2[3][2] = new Option("科沃兹");    select2[3][3] = new Option("迈锐宝");    select2[3][4] = new Option("创酷");    select2[3][5] = new Option("赛欧");    select2[3][6] = new Option("乐风");    select2[3][7] = new Option("科迈罗");    select2[3][7] = new Option("探界者");    //联动函数    function redirec(x) {      var temp = document.gpsiForm.carModel;      if (temp.options.length > 0) {        for (var j = temp.options.length; j >= 0; j--) {          temp.options.remove(i);        }      }      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;    }