public function getSEOScoreCalculation() {

        $this->score_criteria['pagesubject_defined']            = $this->checkPageSubjectDefined();
        $this->score_criteria['pagesubject_in_title']           = $this->checkPageSubjectInTitle();
        $this->score_criteria['pagesubject_in_firstparagraph']  = $this->checkPageSubjectInFirstParagraph();
        $this->score_criteria['pagesubject_in_url']             = $this->checkPageSubjectInUrl();
        $this->score_criteria['pagesubject_in_metadescription'] = $this->checkPageSubjectInMetaDescription();
        $this->score_criteria['numwords_content_ok']            = $this->checkNumWordsContent();
        $this->score_criteria['pagetitle_length_ok']            = $this->checkPageTitleLength();
        $this->score_criteria['content_has_links']              = $this->checkContentHasLinks();
        $this->score_criteria['page_has_images']                = $this->checkPageHasImages();
        $this->score_criteria['content_has_subtitles']          = $this->checkContentHasSubtitles();
        $this->score_criteria['images_have_alt_tags']           = $this->checkImageAltTags();
        $this->score_criteria['images_have_title_tags']         = $this->checkImageTitleTags();


        $this->seo_score = intval(array_sum($this->score_criteria));
    }