用户选择完后在获得所选的checkbox

function getTrace_Id(){

  //get fleetId and truckId 
 
  var numberOfControls=document.form1.length;
  var myElement;
  var c_fleetId;
  var c_truckId; 
  var fleet_Arr = new Array();
  var p_fleetId;
	
  for(var i=0;i<numberOfControls;i++){
  	myElement=document.form1[i];
    if(myElement.type=="checkbox")
    {
      if(myElement.checked==true)
      {
	  	if(myElement.name != "fleetChecBox"){
			c_fleetId = myElement.name;		
			c_fleetId = c_fleetId.substring(c_fleetId.indexOf("_")+1,c_fleetId.length);
			c_truckId = myElement.value;
			fleet_Arr.push(c_truckId+"#"+c_fleetId);
		}
	  }
    }
  }
  p_fleetId = fleet_Arr.join(",");
  return p_fleetId;
}