Identical to file(), except that file_get_contents() returns the file in a string.
備注:This function is binary-safe
心得:You can use a URL as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename and 附錄 I for a list of supported URL protocols.
備注: Context support was added with PHP 5.0
See also: fgets(), file(), fread(), include(), and readfile().