WebGL 使用 jslib 相关

　　从 Unity 弃用两个跟网页相关的API之后, 就开始使用 jslib 了:

[Obsolete("Application.ExternalEval is deprecated. See https://docs.unity3d.com/Manual/webgl-interactingwithbrowserscripting.html for alternatives.")]
public static void ExternalEval(string script);

[Obsolete("Application.ExternalCall is deprecated. See https://docs.unity3d.com/Manual/webgl-interactingwithbrowserscripting.html for alternatives.")]
public static void ExternalCall(string functionName, params object[] args);