2020-05-01 / 2185阅 / 悠然
Finds a pingback server URI based>
Checks the HTML for the rel="pingback" link and x-pingback headers. It does a check for the x-pingback headers first and returns that, if available. The check for the rel="pingback" has more overhead than just the header.
URL to ping.
Default value: ''
(string|false) String containing URI on success, false on failure.