JS implements three-level cascade
This time I will bring you JS to implement three-level cascade. What are the precautions for JS to implement three-level cascade? The following is a practical case, let's take a look.
The example in this article shares with you the specific code for realizing three-level cascading special effects in js for your reference. The specific content is as follows<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title></title> </head> <body> <!-- 实现效果:选择省会出现相应的县下拉框,同时市的下拉框改变--> <script type="application/javascript"> //二维数组存放市的信息 var shi =[["丽水市","杭州市"],["新乡","郑州"]]; //三维数组存放县的信息 var xianes = [[["云和","景宁"],["桐庐","原阳"]],[["卫辉","下乡"],["中原","二七"]]]; //所选的省值 var proIndex = 0; function sgc(){ //获得所选择的省的下拉框值 var pro = document.getElementById("sheng"); //获得市的下拉框 var cit = document.getElementById("shi"); //将省的value与市的一维数组下标所对应 proIndex = pro.value-1; //清空市下拉框中原有的值 cit.options.length = 1; //通过for循环往下拉框中添加市的信息 for(var i = 0;i < shi[proIndex].length;i++){ var op = document.createElement("option"); var citName = document.createTextNode(shi[proIndex][i]); op.value = i; op.appendChild(citName); cit.appendChild(op); } } //市的值改变后改变县的值 function sic(){ var are = document.getElementById("xian"); var cit = document.getElementById("shi"); are.options.length = 1; //通过proIndex获得所选的省的值作为县的数组的一维数组下标,通过cit.value作为县数组的二维数组下标,遍历获得数组值 for(var i = 0;i<xianes[proIndex][cit.value].length;i++){ var op = document.createElement("option"); var areName = document.createTextNode(xianes[proIndex][cit.value][i]); op.value = i; op.appendChild(areName); are.appendChild(op); } } </script> //onchange():控件的value值改变后调用方法 <select id = "sheng" onchange = "sgc();"> <option>----省份---</option> <option value = "1">浙江省</option> <option value = "2">河南省</option> </select> <select id = "shi" onchange="sic();"> <option>---市区---</option> </select> <select id = "xian" > <option>---县区---</option> </select> </body> </html>
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