三级联动

<form method="post" name="myform">     <select name="classid" onchange="select()"></select>     <select name="suid"></select>     <select name="gid"></select> </form> <script language="javascript"> <!-- var arrText = new Array(5); var arrValue = new Array(arrText.length);

function objSetOption(select1, select2, select3) {     this.select1 = select1;     this.select2 = select2;     this.select3 = select3; }

arrText[0]= new objSetOption("选择1:", "选择2_1:,选择2_2:", "选择3_1:,选择3_2:"); arrText[1] = new objSetOption("论文:1", "语文:1,数学:2,英语:3", "初中:2,高中:3"); arrText[2] = new objSetOption("例题:2", "显示b2_1:值b2_1,显示b2_2:值b2_2", "显示b3_1:值b3_1,显示b3_2:值b3_2"); arrText[3] = new objSetOption("显示c:值c", "显示c2_1:值c2_1,显示c2_2:值c2_2", "显示c3_1:值c3_1,显示c3_2:值c3_2"); arrText[4] = new objSetOption("显示d:值d", "显示d2_1:值d2_1,显示d2_2:值d2_2", "显示d3_1:值d3_1,显示d3_2:值d3_2"); arrText[5] = new objSetOption("显示e:值e", "显示e2_1:值e2_1,显示e2_2:值e2_2", "显示e3_1:值e3_1,显示e3_2:值e3_2");

function select(sValue1, sValue2, sValue3) {     var eltSelect1 = document.myform.classid;     var eltSelect2 = document.myform.suid;     var eltSelect3 = document.myform.gid;     var arrSelect1, arrSelect2, arrSelect3;     var arrData1, arrData2, arrData3;     with(eltSelect1) {         var strSelect = options[selectedIndex].value;     }     for(i = 0;i < arrText.length;i ++) {         arrSelect1 = arrText[i].select1;         arrData1 = arrSelect1.split(":");         if (arrData1[1] == strSelect) {             arrSelect2 = (arrText[i].select2).split(",");             for(j = 0;j < arrSelect2.length;j++) {                 arrData2 = arrSelect2[j].split(":");                 with(eltSelect2) {                     length = arrSelect2.length;                     options[j].text = arrData2[0];                     options[j].value = arrData2[1];                     if (arrData2[1] == sValue2) {                         options[j].selected = true;                     }                 }             }             arrSelect3 = (arrText[i].select3).split(",");             for(j = 0;j < arrSelect3.length;j++) {                 arrData3 = arrSelect3[j].split(":");                 with(eltSelect3) {                     length = arrSelect3.length;                     options[j].text = arrData3[0];                     options[j].value = arrData3[1];                     if (arrData3[1] == sValue3) {                         options[j].selected = true;                     }                 }             }             break;         }     } }

function init(sValue1, sValue2, sValue3) {     var eltSelect1 = document.myform.classid;     var eltSelect2 = document.myform.suid;     var eltSelect3 = document.myform.gid;     var arrSelect1, arrSelect2, arrSelect3;     var arrData1, arrData2, arrData3;     if (eltSelect1 != undefined && eltSelect2 != undefined && eltSelect3 != undefined) {         with(eltSelect2) {             arrSelect2 = (arrText[0].select2).split(",");             length = arrSelect2.length;             for(i = 0;i < length;i ++) {                 arrData2 = arrSelect2[i].split(":");                 options[i].text = arrData2[0];                 options[i].value = arrData2[1];             }         }         with(eltSelect3) {             arrSelect3 = (arrText[0].select3).split(",");             length = arrSelect3.length;             for(i = 0;i < length;i ++) {                 arrData3 = arrSelect3[i].split(":");                 options[i].text = arrData3[0];                 options[i].value = arrData3[1];             }         }         with(eltSelect1) {             length = arrText.length;             for(i = 0;i < arrText.length;i ++) {                 arrSelect1 = arrText[i].select1;                 arrData1 = arrSelect1.split(":");                 options[i].text = arrData1[0];                 options[i].value = arrData1[1];                 if (arrData1[1] == sValue1) {                     options[i].selected = true;                     select("", sValue2, sValue3);                 }             }         }     } }

//init(); //默认初始化

init("2", "值b2_1", "值b3_2"); //更改后默认初始化 // --> </script>