下依赖于上的选择框

<script type="text/javascript">
      /*
        查询前对表单进行检查
      */     
      function checkForm(){
          var proFactValue = document.getElementById('proFactValue').value;        
          return checkIntStr(proFactValue,"实测值");
      } 
     
      var xmlHttp;
     
      function createXMLHttpRequest(){
          if(window.ActiveXObject){
           xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
          }else if(window.XMLHttpRequest){
              xmlHttp = new XMLHttpRequest();
          }
      }
     
      function getDetectProjectName(){
          createXMLHttpRequest();
         
          var url = "/fsew/getDetectProjectName?indicatorTypeNO=" + document.getElementsByName("indicatorTypeName")[0].value;
          xmlHttp.open("get",url,true);
          xmlHttp.onreadystatechange = handleStateChange;
          xmlHttp.send(null);
      }
     
      function handleStateChange(){
          if(xmlHttp.readyState == 4){
           if(xmlHttp.status == 200){              
            parseResults();
           }
          }
      }
     
      function parseResults(){//处理返回结果
       var responseText = xmlHttp.responseText.trim();
       if(responseText == "" || responseText == null){
       }else{
        //分解字符串
        var list = responseText.split("-");
        var detectProjectNameDiv = document.getElementById("detectProjectName");
        var i = 0;
        var options = detectProjectNameDiv.options;
        
        //清除
        for(i=options.length-1;i>=0;i=i-1){
         options.remove(i);
        }       
        
        //往select中添加option        
        var item;
        for(i=0;i<list.length-1;i=i+1){
         item = new Option(list[i],i);
         detectProjectNameDiv.options.add(item);
        }
        
       }
      }
  </script>