This is the recommended (W3C) function name for the equivalent:
http://php.net/manual/en/domtext.iswhitespaceinelementcontent.php
See there for additional notes.
(No version information available, might only be in Git)
DOMText::isElementContentWhitespace — Returns whether this text node contains whitespace in element content
This function has no parameters.
This is the recommended (W3C) function name for the equivalent:
http://php.net/manual/en/domtext.iswhitespaceinelementcontent.php
See there for additional notes.