c simulates a simple instance of the js escape method

public static string Escape(string s)
        {
            StringBuilder sb = new StringBuilder();
            byte[] ba = System.Text.Encoding.Unicode.GetBytes(s);
            for (int i = 0; i < ba.Length; i += 2)
            {
                if (ba[i + 1] == 0)
                {
                    // digital , Case letter , As well as "+-*/._" The same 
                    if (
                          (ba[i] >= 48 && ba[i] <= 57)
                        || (ba[i] >= 64 && ba[i] <= 90)
                        || (ba[i] >= 97 && ba[i] <= 122)
                        || (ba[i] == 42 || ba[i] == 43 || ba[i] == 45 || ba[i] == 46 || ba[i] == 47 || ba[i] == 95)
                        )// Remain the same 
                    {
                        sb.Append(Encoding.Unicode.GetString(ba, i, 2));

                    }
                    else//%xx In the form of 
                    {
                        sb.Append("%");
                        sb.Append(ba[i].ToString("X2"));
                    }
                }
                else
                {
                    sb.Append("%u");
                    sb.Append(ba[i + 1].ToString("X2"));
                    sb.Append(ba[i].ToString("X2"));
                }
            }
            return sb.ToString();
        }