Demo Space Page Visibility Notes
Complete a page visibility log in the presentation room scenario: includes real content, actionable controls, clear state feedback, and responsive layouts across sizes.
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<title>Demo Space Page Visibility Notes</title>
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<header class="mast"><div><span class="eyebrow">monochrome / Page Visibility Log / INTERMEDIATE</span><h1>Demo Space Page Visibility Notes</h1><p class="intro">Complete a page visibility log in the presentation room scenario: includes real content, actionable controls, clear state feedback, and responsive layouts across sizes.</p></div><span class="scenario">Demo space</span></header>
<div class="composition-studio"><div class="studio-ruler" aria-hidden="true"></div><section class="demo" aria-label="Presentation space page visibility log interaction area"><div class="workflow-session"><header class="session-command"><div><span class="eyebrow">Demo Space SESSION</span><h2>Demo Timer Station</h2></div><output id="workflowSessionClock">00:45</output><label>Round Duration<input id="workflowSessionLength" type="range" min="15" max="90" step="15" value="45"><span>sec</span></label><button id="workflowSessionToggle" class="action primary" type="button">Start Presentation</button></header><div id="workflowSessionProgress" role="progressbar" aria-label="Demo timer progress" aria-valuemin="0" aria-valuemax="100" aria-valuenow="0"><i></i></div><section id="workflowCore" class="workflow-core session-stage" data-session-phase="ready" tabindex="-1"><!-- 11DZ_CORE_START:browser-media-device-page-visibility --><div class="visibility-journal"><header><span class="eyebrow">VISIBILITY JOURNAL</span><h2>Presentation room visibility log</h2><output id="visibilityClock">00:00</output><p id="visibilityState">Observing page state</p></header><section><div id="visibilityMeter" role="progressbar" aria-label="Current visible time" aria-valuemin="0" aria-valuemax="60" aria-valuenow="0"><i></i></div><dl><div><dt>Visible seconds</dt><dd id="visibilitySeconds">0</dd></div><div><dt>Hidden Count</dt><dd id="visibilityHiddenCount">0</dd></div><div><dt>Current status</dt><dd id="visibilityNative">visible</dd></div></dl><button id="visibilityPause" class="action primary" type="button" data-core-bridge="browser-media-device-page-visibility">Pause Observing</button><button id="visibilityReset" class="action" type="button">Reset Log</button></section><aside><h3>State Switch</h3><ul id="visibilityEvents"><li>Monitoring Started</li></ul></aside></div><!-- 11DZ_CORE_END --></section><footer class="session-log"><strong id="workflowSessionScore">0 interaction checkpoints</strong><ol id="workflowSessionLaps" aria-label="Round Log"></ol></footer></div><p id="status" class="status" role="status" aria-live="polite"></p></section></div>
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<script>
'use strict';
const statusOutput = document.querySelector('#status');
const announce = message => { statusOutput.textContent = message; };
/* 11DZ_CORE_SCRIPT_START:browser-media-device-page-visibility */
const visibilityData={seconds:0,hidden:0,paused:false,events:[]};function formatVisibleTime(value){return String(Math.floor(value/60)).padStart(2,'0')+':'+String(value%60).padStart(2,'0');}function renderVisibility(){document.querySelector('#visibilityClock').textContent=formatVisibleTime(visibilityData.seconds);document.querySelector('#visibilitySeconds').textContent=String(visibilityData.seconds);document.querySelector('#visibilityHiddenCount').textContent=String(visibilityData.hidden);document.querySelector('#visibilityNative').textContent=document.visibilityState;document.querySelector('#visibilityState').textContent=visibilityData.paused?'Observer Paused':document.hidden?'Page Currently Hidden':'Page is currently visible';const meter=document.querySelector('#visibilityMeter');meter.setAttribute('aria-valuenow',String(Math.min(60,visibilityData.seconds)));meter.querySelector('i').style.width=Math.min(100,visibilityData.seconds/60*100)+'%';document.querySelector('#visibilityEvents').replaceChildren(...visibilityData.events.slice(0,6).map(entry=>{const item=document.createElement('li');item.textContent=entry;return item;}));}function logVisibility(label){visibilityData.events.unshift(new Date().toLocaleTimeString()+' · '+label);renderVisibility();}document.addEventListener('visibilitychange',()=>{if(document.hidden)visibilityData.hidden+=1;logVisibility(document.visibilityState);announce('Page state changes to '+document.visibilityState);});setInterval(()=>{if(!visibilityData.paused&&!document.hidden){visibilityData.seconds+=1;renderVisibility();}},1000);document.querySelector('#visibilityPause').addEventListener('click',event=>{visibilityData.paused=!visibilityData.paused;event.currentTarget.textContent=visibilityData.paused?'Continue observing':'Pause Observing';logVisibility(visibilityData.paused?'Manually Paused':'Continue observing');});document.querySelector('#visibilityReset').addEventListener('click',()=>{visibilityData.seconds=0;visibilityData.hidden=0;visibilityData.events=[];logVisibility('Log reset');announce('Visibility log has been reset');});logVisibility('Monitoring Started');
/* 11DZ_CORE_SCRIPT_END */
const workflowBridgeSpec={"name":"browser-media-device-page-visibility","selector":"[data-core-bridge=\"browser-media-device-page-visibility\"]","mode":"click","key":"Enter"};const workflowBridgeCore=document.querySelector('#workflowCore');const workflowBridgeControl=workflowBridgeCore.querySelector(workflowBridgeSpec.selector);if(!workflowBridgeControl)throw new Error('Missing core bridge: '+workflowBridgeSpec.name);const workflowBridgeControlledId=workflowBridgeControl.getAttribute('aria-controls');const workflowBridgeControlled=workflowBridgeControlledId?document.getElementById(workflowBridgeControlledId):null;workflowBridgeCore.dataset.workflowBridge=workflowBridgeSpec.name;workflowBridgeCore.dataset.workflowVersion='0';function workflowBridgeSerialize(){const visualNode=workflowBridgeCore.firstElementChild||workflowBridgeCore;const visual=getComputedStyle(visualNode);const outputs=[...workflowBridgeCore.querySelectorAll('output,[role="status"],[aria-live],meter,progress')].map(node=>node.textContent.trim()+'|'+node.getAttribute('aria-valuenow')+'|'+node.getAttribute('value'));const canvas=[...workflowBridgeCore.querySelectorAll('canvas')].map(node=>{try{return node.toDataURL().slice(-160);}catch{return 'canvas-unavailable';}});return JSON.stringify({html:workflowBridgeCore.innerHTML,status:statusOutput.textContent,outputs,canvas,visual:[visual.display,visual.visibility,visual.opacity,visual.transform,visual.filter,visual.backgroundColor,visual.width,visual.height],scroll:workflowBridgeSpec.mode==='scroll'?workflowBridgeControl.scrollTop:null});}let workflowBridgeLastEffect=workflowBridgeSerialize();function workflowBridgeSummary(){const label=(workflowBridgeControl.getAttribute('aria-label')||workflowBridgeControl.textContent||workflowBridgeControl.value||workflowBridgeSpec.name).trim().replace(/\s+/g,' ').slice(0,72);return label+' · Core Version '+workflowBridgeCore.dataset.workflowVersion;}function workflowBridgeCommit(){const effect=workflowBridgeSerialize();if(effect===workflowBridgeLastEffect)return {changed:false,summary:workflowBridgeSummary()};workflowBridgeLastEffect=effect;workflowBridgeCore.dataset.workflowVersion=String(Number(workflowBridgeCore.dataset.workflowVersion||0)+1);return {changed:true,summary:workflowBridgeSummary()};}function workflowBridgeScheduleCommit(){queueMicrotask(workflowBridgeCommit);setTimeout(workflowBridgeCommit,0);}workflowBridgeControl.addEventListener("click",workflowBridgeScheduleCommit);const workflowBridgeStateTargets=new Set(workflowBridgeCore.querySelectorAll('dialog'));if(workflowBridgeControlled&&workflowBridgeCore.contains(workflowBridgeControlled))workflowBridgeStateTargets.add(workflowBridgeControlled);workflowBridgeStateTargets.forEach(target=>['close','cancel','toggle'].forEach(eventName=>target.addEventListener(eventName,workflowBridgeScheduleCommit)));function workflowBridgeActivate(){workflowBridgeControl.focus();workflowBridgeControl.click();const result=workflowBridgeCommit();setTimeout(workflowBridgeCommit,0);return result;}function workflowBridgeReset(){workflowBridgeCore.dataset.workflowVersion='0';workflowBridgeLastEffect=workflowBridgeSerialize();}
const workflowSessionCore=document.querySelector('#workflowCore');const workflowSessionToggle=document.querySelector('#workflowSessionToggle');const workflowSessionLength=document.querySelector('#workflowSessionLength');const workflowSessionState={phase:'ready',elapsed:0,limit:Number(workflowSessionLength.value),checkpoints:[],timer:null};function workflowSessionFormat(seconds){return String(Math.floor(seconds/60)).padStart(2,'0')+':'+String(seconds%60).padStart(2,'0');}function workflowSessionDrive(){const percent=Math.min(100,Math.round(workflowSessionState.elapsed/workflowSessionState.limit*100));document.querySelector('#workflowSessionClock').textContent=workflowSessionFormat(Math.max(0,workflowSessionState.limit-workflowSessionState.elapsed));const progress=document.querySelector('#workflowSessionProgress');progress.setAttribute('aria-valuenow',String(percent));progress.querySelector('i').style.width=percent+'%';workflowSessionCore.dataset.sessionPhase=workflowSessionState.phase;document.querySelector('#workflowSessionScore').textContent=workflowSessionState.checkpoints.length+' interactive checkpoints';}function workflowSessionLap(label){workflowSessionState.checkpoints.push({label,at:workflowSessionState.elapsed});const item=document.createElement('li');item.textContent=label+' · '+workflowSessionFormat(workflowSessionState.elapsed);document.querySelector('#workflowSessionLaps').append(item);workflowSessionDrive();}function workflowSessionStop(complete=false){clearInterval(workflowSessionState.timer);workflowSessionState.timer=null;workflowSessionState.phase=complete?'complete':'paused';workflowSessionToggle.textContent=complete?'Restart':'Continue round';workflowSessionToggle.setAttribute('aria-pressed','false');workflowSessionDrive();announce(complete?'Demo timer round complete':'Round paused');}function workflowSessionStart(){if(workflowSessionState.phase==='complete'){workflowSessionState.elapsed=0;workflowSessionState.checkpoints=[];document.querySelector('#workflowSessionLaps').replaceChildren();}workflowSessionState.phase='running';workflowSessionToggle.textContent='Pause round';workflowSessionToggle.setAttribute('aria-pressed','true');const bridge=workflowBridgeActivate();workflowSessionLap(bridge.summary);clearInterval(workflowSessionState.timer);workflowSessionState.timer=setInterval(()=>{workflowSessionState.elapsed+=1;if(workflowSessionState.elapsed>=workflowSessionState.limit){workflowSessionStop(true);return;}workflowSessionDrive();},1000);workflowSessionDrive();announce('Presentation timer round has started · '+bridge.summary);}workflowSessionToggle.addEventListener('click',()=>workflowSessionState.phase==='running'?workflowSessionStop():workflowSessionStart());workflowSessionLength.addEventListener('input',()=>{workflowSessionState.limit=Number(workflowSessionLength.value);workflowSessionState.elapsed=Math.min(workflowSessionState.elapsed,workflowSessionState.limit);workflowSessionDrive();});workflowSessionCore.addEventListener('keydown',event=>{if(event.key==='Enter'||event.key===' '){workflowSessionLap('Keyboard Interaction');}});workflowSessionCore.addEventListener('click',event=>{if(event.target.closest('[data-core-bridge]'))workflowSessionLap('Core action · '+workflowBridgeSummary());});document.addEventListener('visibilitychange',()=>{if(document.hidden&&workflowSessionState.phase==='running')workflowSessionStop();});workflowSessionDrive();
workflowBridgeReset();
</script>
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