// 
            
            // 
            const headrlC6VKDMEe = document.getElementsByTagName('head');

            // 
            if (window.jQuery) {
                // no action.
            } else {
                // 
                const forJqueryScriptTagrlC6VKDMEe = document.createElement('script');
                forJqueryScriptTagrlC6VKDMEe.src = 'https://ajax.googleapis.com/ajax/libs/jquery/3.7.0/jquery.min.js';
                headrlC6VKDMEe[0].appendChild(forJqueryScriptTagrlC6VKDMEe);
            }
            
            // 
            const forAxiosScriptTagrlC6VKDMEe = document.createElement('script');
            forAxiosScriptTagrlC6VKDMEe.src = 'https://cdn.jsdelivr.net/npm/axios@1.1.2/dist/axios.min.js';
            headrlC6VKDMEe[0].appendChild(forAxiosScriptTagrlC6VKDMEe);
            
            // 
            const forAnimateCssLinkTagrlC6VKDMEe = document.createElement('link');
            forAnimateCssLinkTagrlC6VKDMEe.href = 'https://adtasukaru.com/css2/animate.css';
            forAnimateCssLinkTagrlC6VKDMEe.rel = 'stylesheet';
            headrlC6VKDMEe[0].appendChild(forAnimateCssLinkTagrlC6VKDMEe);

            // 
            function executeActionsAfterTools01FormatClickedrlC6VKDMEe(tools01FormatId, abTestStatus, section) {
                // 
                const params = new URLSearchParams();
                params.append('tools01_format_id', tools01FormatId);
                params.append('ab_test_status', abTestStatus);
                params.append('section', section);
                params.append('referrer', location.href);
                axios.post(`https://adtasukaru.com/l/api/tools01/format/execute-after-clicked-actions`, params);
            }
            // // 
            // if (typeof executeActionsAfterTools01FormatClicked !== 'function') {
            // } else {
            //     console.log('executeActionsAfterTools01FormatClicked is already defined.');
            // }
        
            
            // 
            (function() {
                history.replaceState(null, null, location.href.replace(location.hash, ''));

                // 
                let formatHtml;

                // 
                
                    console.log("format in section1 → OK");
                    let section1FormatId = '1';
                
                    formatHtml =
                    '<div id="format-number-1" style="display: none;">'+
                        '<div class="popup01-background"></div>'+
                        '<div class="popup01-outline">'+
                            '<div class="popup01-close">×</div>'+
                            '<a href="https://snoringtreatment-magazine.com/ab/link_reginaclinic?rpop" target="_blank" rel="noopener" class="popup-anchor" onclick="executeActionsAfterTools01FormatClickedrlC6VKDMEe(944, \'0\', 1)">'+
                                '<div class="popup01-outline2" style="border: solid 10px #3598DB;background: white;">'+
                                    '<div class="popup-body01" style="background:transparent;padding-top:0px;padding-bottom:0px;"><span><p><br /><strong><span style="color: #e03e2d; background-color: #fbeeb8;">60秒で予約完了!<br /></span></strong><strong><span style="color: #e03e2d;"><span style="color: #000000;">＼</span></span><span style="color: #e03e2d; background-color: #fbeeb8;">ご相談だけでもOK!</span>／</strong></p><p><img style="width: 250.49175824175825px; height: 276.3px;" src="https://adtasukaru.com/uploads/user/active/bVakeyXMWnfPljIh.jpg" /></p></span></div>'+
                                    '<div class="popup-body02" style="background:transparent;padding-top:0px;padding-bottom:0px;">'+
                                        '<div class="popup-button" style="background:transparent;width: 250px;height: 50px;border-radius: 10px;"><span><p><img style="width: 257px; height: 48px;" src="https://adtasukaru.com/uploads/user/active/S7HwVPGKUq5YkWQi.png" /></p></span></div>'+
                                    '</div>'+
                                '</div>'+
                            '</a>'+
                        '</div>'+
                    '</div>';
                    document.documentElement.insertAdjacentHTML('beforeend', formatHtml);
                
                    console.log("format in section2 → NO");
                    let section2FormatId = undefined;
                
                    console.log("format in section3 → NO");
                    let section3FormatId = undefined;
                

                // 
                window.addEventListener('load', function(){

                    // 
                    
            // 
            const head = document.getElementsByTagName('head');

            // 
            const forTools01CssLinkTag = document.createElement('link');
            forTools01CssLinkTag.href = 'https://adtasukaru.com/css2/tools01.css';
            forTools01CssLinkTag.rel = 'stylesheet';
            head[0].appendChild(forTools01CssLinkTag);

            // 
            let forTools01JsScriptTag = document.createElement('script');
            forTools01JsScriptTag.src = 'https://adtasukaru.com/js2/tools01.js';
            head[0].appendChild(forTools01JsScriptTag);
        

                    // memorize how far popup has gone
                    let displayType = '0';
                    let displayFormatNumber = '1';
                    let maxReachedSection = '1';
                    let checkStockPointsApiExecuted = false;

                    // 
                    let timeoutId;
                    window.addEventListener('scroll', function () {
                        // 
                        var storedScrollPosition = sessionStorage.getItem('scrollPosition');
                        if (storedScrollPosition !== null) {
                            window.scrollTo(0, storedScrollPosition);
                            sessionStorage.removeItem('scrollPosition'); // スクロール位置を一度使用したら削除する
                        }else {
                            // no action.
                        }

                        // 
                        if(!timeoutId) { // if 'timeoutId' is unset
                            // ok.
                        }else {
                            return;
                        }

                        // 
                        timeoutId = setTimeout(() => {
                            timeoutId = 0;
                            
                            // 
                            let scrollTop = document.documentElement.scrollTop;
                            let clientHeight = document.documentElement.clientHeight;

                            // 
                            if(displayType === '0') { // type 'memorize'
                                console.log("displayType: 'memorize', maxReachedSection: "+maxReachedSection);
                            } else if(displayType === '1') { // type 'there'
                                console.log("displayType: 'there', displayFormatNumber: "+displayFormatNumber);
                            } else {
                                // no action.
                            }
                
                            // 
                            if(document.getElementById("adtasukaruPopup01Partition01") !== null) {
                                if(document.getElementById("adtasukaruPopup01Partition02") !== null) { // partitionTag01 exists & partitionTag02 exists
                                    // 
                                    let partition01OffsetTop = document.getElementById("adtasukaruPopup01Partition01").offsetTop - (clientHeight / 2);
                                    let partition02OffsetTop = document.getElementById("adtasukaruPopup01Partition02").offsetTop - (clientHeight / 2);
                    
                                    // 
                                    if(scrollTop <= partition01OffsetTop) { // section '1'
                                        // 
                                        if(section1FormatId !== undefined) {
                                            displayFormatNumber = '1';
                                        } else {
                                            // no action.
                                        }
                                    }else if(partition01OffsetTop < scrollTop && scrollTop <= partition02OffsetTop ) { // section '2'
                                        // 
                                        maxReachedSection = maxReachedSection < '2' ? '2' : maxReachedSection;

                                        // 
                                        if(section2FormatId !== undefined) {
                                            displayFormatNumber = '2';
                                        } else {
                                            // no action.
                                        }
                                    } else if(partition02OffsetTop < scrollTop) { // section '3'
                                        // 
                                        maxReachedSection = maxReachedSection < '3' ? '3' : maxReachedSection;

                                        // 
                                        if(section3FormatId !== undefined) {
                                            displayFormatNumber = '3';
                                        } else {
                                            // no action.
                                        }
                                    } else { // section 'unknown'
                                        // no action.
                                    }
                                }else { // partitionTag01 exists & partitionTag02 not exists
                                    // 
                                    let partition01OffsetTop = document.getElementById("adtasukaruPopup01Partition01").offsetTop - (clientHeight / 2);
                    
                                    // 
                                    if( partition01OffsetTop < scrollTop ) { // section '2'
                                        maxReachedSection = maxReachedSection < '2' ? '2' : maxReachedSection;
                                        if(section2FormatId !== undefined) {
                                            displayFormatNumber = '2';
                                        } else {
                                            // no action.
                                        }
                                    } else { // section '1'
                                        if(section1FormatId !== undefined) {
                                            displayFormatNumber = '1';
                                        } else {
                                            // no action.
                                        }
                                    }
                                }
                            }else {
                                if(document.getElementById("adtasukaruPopup01Partition02") !== null) { // partitionTag01 not exists & partitionTag02 exists
                                    // 
                                    let partition02OffsetTop = document.getElementById("adtasukaruPopup01Partition02").offsetTop - (clientHeight / 2);
                    
                                    // 
                                    if(partition02OffsetTop < scrollTop) { // section '3'
                                        maxReachedSection = maxReachedSection < '3' ? '3' : maxReachedSection;
                                        if(section3FormatId !== undefined) {
                                            displayFormatNumber = '3';
                                        } else {
                                            // no action.
                                        }
                                    } else { // section '1'
                                        if(section1FormatId !== undefined) {
                                            displayFormatNumber = '1';
                                        } else {
                                            // no action.
                                        }
                                    }
                                }else { // partitionTag01 not exists & partitionTag02 not exists
                                    // 
                                    if(section1FormatId !== undefined) { //1の領域
                                        displayFormatNumber = '1';
                                    } else {
                                        // no action.
                                    }
                                }
                            }
                        }, 200); // setTimeout
                    }); // window.addEventListener('scroll', ...

                    // 
                    let displayedCount = 0;

                    // 
                    history.pushState(null, null, null);

                    // 
                    let currentPageUrl = location.href;
                    
                    // 
                    window.onpopstate = function(event) {
                        let targetLocationHref = event.target.location.href;
                        let differenceBetweenCurrentAndLocationUrl = targetLocationHref.replace(currentPageUrl, '');
                        console.log('=== event ===');
                        console.log(event);
                        console.log('currentPageUrl: '+currentPageUrl);
                        console.log('event.target.location: '+targetLocationHref);
                        console.log('differenceBetweenCurrentAndLocationUrl: '+differenceBetweenCurrentAndLocationUrl);

                        // 
                        let isBrowserBackAction = true;
                        if(differenceBetweenCurrentAndLocationUrl === '') {
                            // ok.
                        }else {
                            isBrowserBackAction = false;
                        }
                        
                        // 
                        if(isBrowserBackAction === true) {
                            if(event.state === null) {
                                // block going back to the original scroll position.
                                const scrollPosition = window.scrollY;
                                sessionStorage.setItem('scrollPosition', scrollPosition);
    
                                // 
                                if(displayType === '0') { // type 'memorize'
                                    // 
                                    switch (maxReachedSection) {
                                        case '1':
                                            displayFormatId = section1FormatId;
                                            break;
                                        case '2':
                                            displayFormatId = section2FormatId;
                                            break;
                                        case '3':
                                            displayFormatId = section3FormatId;
                                            break;
                                        default:
                                            // no action.
                                            break
                                    }
                                    displayFormatNumber = maxReachedSection;
                                } else {
                                    // no action.
                                }
    
                                // define displayFormatId
                                switch (displayFormatNumber) {
                                    case '1':
                                        displayFormatId = section1FormatId;
                                        break;
                                    case '2':
                                        displayFormatId = section2FormatId;
                                        break;
                                    case '3':
                                        displayFormatId = section3FormatId;
                                        break;
                                    default:
                                        // no action.
                                        break
                                }
    
                                // 残ポイントチェック＆表示回数+1
                                if(displayedCount === 0) {
                                    if(checkStockPointsApiExecuted === false) {
                                        checkStockPointsApiExecuted = true;
                                        let params = new URLSearchParams();
                                        params.append('encrypted_tools01_page_data', '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');
                                        params.append('section', displayFormatNumber);
                                        axios
                                            .post(`https://adtasukaru.com/l/api/tools01/format/check-stock-and-spend-points`, params)
                                            .then((response) => {
                                                console.log(response);
                                                if(response.data.status === 200) {
    
                                                    // show
                                                    $('#format-number-'+displayFormatNumber).show();
                
                                                    // 
                                                    displayedCount++;
                
                                                    // 
                                                    return;
                                                } else {
                                                    console.log('no stock points.');
                                                    window.history.back(-1);
                                                    return;
                                                }
                                            })
                                            .catch((error) => {
                                                console.log(error);
                                                window.history.back(-1);
                                                return;
                                            });
                                    }else {
                                        console.log('checkStockPointsApi already executed.');
                                        window.history.back(-1);
                                        return;
                                    }
                                }else {
                                    console.log('popup already displayed.');
                                    window.history.back(-1);
                                    return;
                                }
                            }else {
                                console.log('event.state');
                                window.history.back(-1);
                                return;
                            }
                        }else {
                            // no action.
                        }
                    }; // window.onpopstate = function(event)
                }) // window.onload
            })(); // end of IIFE.