原生JavaScript实现二级联动菜单

<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 <title>二级联动菜单</title>
 <style>
  *{
  padding: 0px;
  margin: 0px;
  }
  form{
  width: 300px;
  height: 300px;
  margin: 10px auto;
  }
  form select{
  width: 140px;
  height: 50px;
  text-align: center;
  line-height: 30px;
  font-size: 20px;
  }
 </style>
 <script>
  var x = ["请选择...","美食","景点","电影"];
  var y = [
  ["请选择..."],
  ["黄焖鸡","油焖大虾","红烧肉","东坡肉"],
  ["黄山","泰山","嵩山","华山"],
  ["烈日灼心","逆战","无间道","黑金"]
  ];
  window.onload = init;
  function init(){
  var chose1 = document.getElementById("chose1");
  var chose2 = document.getElementById("chose2");
  chose1.length = x.length;
  for(var i = 0;i<x.length;i++)
  {
   chose1.options[i].text = x[i];
  }
  var index = 0;
  chose2.length = y[index].length;
  for(var j = 0;j<y[index].length;j++)
  {
   chose2.options[j].text = y[index][j];
  }
  }
  function change(obj){
  var chose2 = document.getElementById("chose2");
  chose2.length = y[obj].length;
  for(var j = 0;j<y[obj].length;j++)
  {
   chose2.options[j].text = y[obj][j];
  }
  }
 </script>
 </head>
 <body>
 <form>
  <select id="chose1" onchange="change(this.selectedIndex)"></select>
  <select id="chose2"></select>
 </form>
 </body>
</html>