This function should be called after you initialize a
CURL session and all the options for the session are set. Its
purpose is simply to execute the predefined CURL session
(given by the ch).
提示: 任何直接把輸出到瀏覽器的結果,可使用輸出控制函數來擷取 此函數的輸出,在將之存入一個 字串(舉例說明)。