Carry out hitTest with two child

Question

I've been trying to carry out hitTest with the two child. They are namely enemy and weapon. However, it seems not working. I had been attempting to sort it out myself and searched the Internet but I got no idea of how to solve it. Please help if you know it! Many thanks!
stage.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
function enterFrameHandler(event:Event)
     if (char_mc.x + char_width > stage.stageWidth)
          char_mc.x = stage.stageWidth - char_width;
     else if (char_mc.x-char_width<0)
          char_mc.x = char_width;
     if (char_mc.hitTestObject(enemy))
          char_mc.gotoAndPlay(31);
          stage.removeEventListener(KeyboardEvent.KEY_UP, KeyUpHandler);
          stage.removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
          stage.removeEventListener(KeyboardEvent.KEY_DOWN, charControl);
          new_x = 0;
          removeChild(enemy);
     if (weapon.hitTestObject(enemy))
          removeChild(enemy);

Answer 1

After I tried tracing the collision, it showed there was no collision detected. I would paste all the code here for your convenience. Thanks!
P.S. In this game, you can control the character movement by clicking left or right on keyboard. And attack the enemy by pressing spacebar. It is expected when the weapon hit the enemy, the enemy will disappear.
import flash.events.KeyboardEvent;
import flash.events.Event;
import flash.display.MovieClip;
import flash.utils.Timer;
import flash.events.TimerEvent;
stop();
var pressKey:Boolean=false;
var dx:Number;
dx = char_mc.x;
var new_x:Number = 0;
var char_width:Number = char_mc.width / 2;
var mp:Number = 1000;
var enemy:Enemy = new Enemy();
addChild(enemy);
enemy.x = 820;
enemy.y = 150;
var weapon:Weapon = new Weapon();
var mpTimer:Timer = new Timer(25);
mpTimer.start();
stage.addEventListener(Event.ENTER_FRAME, refreshX);
stage.addEventListener(KeyboardEvent.KEY_DOWN, charControl);
stage.addEventListener(KeyboardEvent.KEY_UP, KeyUpHandler);
stage.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
mpTimer.addEventListener(TimerEvent.TIMER, addMP);
function addMP(event:TimerEvent)
     if (mp < 1000)
          mp +=  1;
     else{
          mp=1000;
function enterFrameHandler(event:Event)
{mpText.text= "MP: " + String(mp);
     if (char_mc.x + char_width > stage.stageWidth)
          char_mc.x = stage.stageWidth - char_width;
     else if (char_mc.x-char_width<0)
          char_mc.x = char_width;
     if (char_mc.hitTestObject(enemy))
          char_mc.gotoAndPlay(31);
          stage.removeEventListener(KeyboardEvent.KEY_UP, KeyUpHandler);
          stage.removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
          stage.removeEventListener(KeyboardEvent.KEY_DOWN, charControl);
          new_x = 0;
          removeChild(enemy);
     if (weapon.hitTestObject(enemy))
          removeChild(enemy);
          trace("success");
function charControl(event:KeyboardEvent)
     switch (event.keyCode)
          case Keyboard.RIGHT :
               new_x = 4;
               char_mc.play();
               break;
          case Keyboard.LEFT :
               new_x = -4;
               char_mc.play();
               break;
          case Keyboard.SPACE :
          if(mp>150 && pressKey==false){
               var weapon:Weapon = new Weapon();
               addChild(weapon);
               weapon.x = char_mc.width*1.75 + char_mc.x;
               weapon.y = 190;
               mp-=150;
               pressKey=true;
               break;
function KeyUpHandler(event:KeyboardEvent)
     switch (event.keyCode)
          case Keyboard.RIGHT :
               new_x = 0;
               char_mc.stop();
               break;
          case Keyboard.LEFT :
               new_x = 0;
               char_mc.stop();
     pressKey=false;
function refreshX(event:Event)
     dx = char_mc.x;
     char_mc.x = dx + new_x;