var typeID,firstID,secondID;
function selectstype(type,ID1,ID2){ 
		 typeID=type;
     firstID=ID1;
     secondID=ID2;
		 sentbtype('selectbusintype.php?firstID='+document.getElementById(firstID).value);	
}

function sentbtype(url){        
		  http_request = false;
		  if(window.XMLHttpRequest) { //Mozilla 浏览器
              http_request = new XMLHttpRequest();
              if (http_request.overrideMimeType) {//设置MiME类别
                  http_request.overrideMimeType('text/xml');
              }
      }else if(window.ActiveXObject) { // IE浏览器
              try {
                         http_request = new ActiveXObject("Msxml2.XMLHTTP");
              }catch(e){
                         try{
                              http_request = new ActiveXObject("Microsoft.XMLHTTP");
                         }catch(e){}
              }
      }
		  if (!http_request) { 
             window.alert("不能创建XMLHttpRequest对象实例.");
             return false;
      }

      http_request.onreadystatechange = processRequest;
      http_request.open("GET", url, true);
      http_request.setRequestHeader("If-Modified-Since","0"); 
      http_request.send(null);
}
function processRequest() {
			var num=document.getElementById(secondID).options.length;
		  for(var ii=0;ii<num;ii++){
		         document.getElementById(secondID).options[0] = null; 
		  }
      if(http_request.readyState == 4){ 	   
         if(http_request.status == 200){
				    var row=http_request.responseText;
				    createoption(row,document.getElementById(secondID))
         }
		  }
}

function createoption(rows,obj){      
        var rowss=rows.split("|"); 
		    for(var i=0;i<rowss.length-1;i++){
				      if(typeID==1){
							        var   opt   =   new  Option(rowss[i],rowss[i]);   
                      obj.options.add(opt);
					    }else if(typeID==2){
						          var   opt   =   new  Option(rowss[i],rowss[i]);   
                      obj.options.add(opt);
					    }else if(typeID==3){
							       var detailrow=rowss[i].split(",");
							       var   opt   =   new  Option(detailrow[1],detailrow[0]);   
                     obj.options.add(opt);
					    }
					    
		     }
}