src/HtmlElementAbstract.php
public function setContent($content)
    {
        if (!is_null($content)) {
            if ($content instanceof HtmlElementInterface) {
                $htmlElementObject = $content;
            } else {
                $htmlElementObject = new HtmlElementContent($content);
            }
            $this->getChildElementCollection()->clear();
            $this->getChildElementCollection()->add($htmlElementObject);
        }
        return $this;
    }
public function setContent($content)
    {
        if (!is_null($content)) {
            if ($content instanceof HtmlElementInterface) {
                $htmlElementObject = $content;
            } else {
                $htmlElementObject = new HtmlElementContent($content);
            }
            $this->getChildElementCollection()->clear();
            $this->getChildElementCollection()->add($htmlElementObject);
        }
        return $this;
    }
set html element content, replace all child elements

@param       string      $content        html element content
@return      HtmlElementAbstract