Browser Media and Device Capabilities

Presentation space viewport inspector

Complete the viewport information panel in a presentation-space scenario: includes real content, actionable controls, clear status feedback, and responsive layouts across sizes.

Browser Media and Device CapabilitiesViewport Information PanelHTMLCSSBrowser API
With JavaScript enabled, you can edit, run, and save this example. The fixed source is as follows:
<!doctype html>
<html lang="en" dir="ltr">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Presentation space viewport inspector</title>
  <style>
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  </style>
</head>
<body data-aesthetic="art-deco" data-composition="control-deck">
  <main class="page">
    <header class="mast"><div><span class="eyebrow">art-deco / viewport information panel / INTERMEDIATE</span><h1>Presentation space viewport inspector</h1><p class="intro">Complete the viewport information panel in a presentation-space scenario: includes real content, actionable controls, clear status feedback, and responsive layouts across sizes.</p></div><span class="scenario">Demo space</span></header>
    <div class="composition-deck"><div class="deck-bar"><span>CONTROL DECK · 04</span><span>Viewport Information Panel</span><span class="deck-lights" aria-hidden="true"><i></i><i></i><i></i></span></div><section class="demo" aria-label="Interactive area for the presentation space viewport information panel"><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-viewport-inspector --><div class="viewport-lab"><header><span class="eyebrow">VIEWPORT RULER</span><h2>Presentation Space Viewport Measurement Station</h2><output id="viewportReading">—</output><button id="viewportCapture" class="action primary" type="button" data-core-bridge="browser-media-device-viewport-inspector">Record current size</button></header><section class="viewport-board" aria-label="Viewport Size Diagram"><i id="viewportWidthBar"></i><i id="viewportHeightBar"></i><dl><div><dt>Content Area</dt><dd id="viewportInner">—</dd></div><div><dt>Available screen area</dt><dd id="viewportScreen">—</dd></div><div><dt>Pixel density</dt><dd id="viewportDpr">—</dd></div><div><dt>Screen Orientation</dt><dd id="viewportOrientation">—</dd></div></dl></section><aside><h3>Size Snapshot</h3><ol id="viewportHistory"><li>Record the comparison after resizing the window</li></ol></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>
  </main>
  <script>
    'use strict';
    const statusOutput = document.querySelector('#status');
    const announce = message => { statusOutput.textContent = message; };
    /* 11DZ_CORE_SCRIPT_START:browser-media-device-viewport-inspector */
const viewportHistory=[];const viewportReading=document.querySelector('#viewportReading');function measureViewport(){const width=innerWidth;const height=innerHeight;const orientation=width>=height?'horizontal':'Portrait';viewportReading.textContent=width+' × '+height;document.querySelector('#viewportInner').textContent=document.documentElement.clientWidth+' × '+document.documentElement.clientHeight;document.querySelector('#viewportScreen').textContent=screen.availWidth+' × '+screen.availHeight;document.querySelector('#viewportDpr').textContent=(devicePixelRatio||1).toFixed(2)+' dppx';document.querySelector('#viewportOrientation').textContent=orientation;document.querySelector('#viewportWidthBar').style.width=Math.min(100,width/16)+'%';document.querySelector('#viewportHeightBar').style.height=Math.min(100,height/10)+'%';}function captureViewport(){viewportHistory.unshift({width:innerWidth,height:innerHeight,dpr:devicePixelRatio||1,at:new Date()});viewportHistory.splice(5);document.querySelector('#viewportHistory').replaceChildren(...viewportHistory.map(entry=>{const item=document.createElement('li');item.textContent=entry.width+' × '+entry.height+' · '+entry.dpr.toFixed(1)+'x';return item;}));announce('Recorded # '+viewportHistory.length+' viewport snapshots');}addEventListener('resize',measureViewport,{passive:true});document.querySelector('#viewportCapture').addEventListener('click',captureViewport);measureViewport();
/* 11DZ_CORE_SCRIPT_END */
const workflowBridgeSpec={"name":"browser-media-device-viewport-inspector","selector":"[data-core-bridge=\"browser-media-device-viewport-inspector\"]","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>
</body>
</html>
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