javawscript 三级菜单的实现原理

省份:
城市:
区县:

  

  

  省份,城市,区县数据结构:【名称,父类ID,当前ID】

  onChange="changelocation2(document.editForm.smalllocation.options[document.editForm.smalllocation.selectedIndex].value)"

  根据selectedIndex取得下一级关联菜单的父类ID,

  

复制代码 代码如下:

  function changelocation(locationid)

  {

  document.editForm.smalllocation.length = 0;

  // document.editForm.dlmc0.length = 0;

  document.getElementById("dlmc0").length=0;

  //document.editForm.dlmc0.options[0] = new Option('==请选择==','');

  document.getElementById("dlmc0").options[0] = new Option('==请选择==','');

  //alert(locationid);

  var locationid=locationid;

  var i;

  document.editForm.smalllocation.options[0] = new Option('==请选择==','');

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

  {

  if (subcat[i][1] == locationid)

  {

  document.editForm.smalllocation.options[document.editForm.smalllocation.length] = new Option(subcat[i][0], subcat[i][2]);

  }

  }

  }