Merge pull request #110 from frugan-dev/master

fix: Cannot assign null to property DOMNode::* of type string

Author: voku

src/voku/helper/AbstractSimpleHtmlDom.php

@@ -180,7 +180,9 @@ public function __set($name, $value)
                         $value = (string)$value;
                     }
 
-                    return $this->node->{$nameOrig} = $value;
+                    if (!is_null($value)) {
+                        return $this->node->{$nameOrig} = $value;
+                    }
                 }
 
                 return $this->setAttribute($name, $value);