Unity3D报警告"Implicit downcast"？

Question

在做unity的入门练习

LevelScript.js

#pragma strict

var experience : int;
    
function Level() : int
{
    return experience / 750; 
}

LevelScriptEditor.js

#pragma strict

@CustomEditor (LevelScript)
class LevelScriptEditor extends Editor 
{
    function OnInspectorGUI()
    {   
        var myLevelScript : LevelScript = target;
        
        myLevelScript.experience = EditorGUILayout.IntField("Experience", myLevelScript.experience);
        EditorGUILayout.LabelField("Level", myLevelScript.Level().ToString());
    }
}

（视频用的是c#，不过我比较熟悉javscript,就用了javascript的格式）

虽然最后程序成功了，但是unity报了警告有点在意。有人知道是什么意思么？

Assets/Editor/LevelScriptEditor.js(8,42): BCW0028: WARNING: Implicit downcast from 'UnityEngine.Object' to 'LevelScript'.