Browser Media and Device Capabilities

Presentation space local storage note

Complete Local Storage Notes for the presentation space scenario: includes real content, interactive controls, clear state feedback, and responsive layouts.

Browser Media and Device CapabilitiesLocal Storage Sticky NotesHTMLCSSBrowser API
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  <main class="page">
    <header class="mast"><div><span class="eyebrow">paper / local storage note / BEGINNER</span><h1>Presentation space local storage note</h1><p class="intro">Complete Local Storage Notes for the presentation space scenario: includes real content, interactive controls, clear state feedback, and responsive layouts.</p></div><span class="scenario">Demo space</span></header>
    <figure class="composition-gallery"><section class="demo" aria-label="Demo space local storage note 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-local-storage --><div class="storage-notebook"><aside><span class="eyebrow">LOCAL STORAGE</span><h2>Presentation Space Offline Notes</h2><p>Save actions are written to the browser first; in restricted environments, this page’s memory is used automatically.</p><output id="storageMode">Checking storage capabilities</output></aside><form id="storageForm"><label>Title<input id="storageTitle" required value="Presentation room notes"></label><label>Label<select id="storageTag"><option>To be processed</option><option>Inspiration</option><option>Completed</option></select></label><label class="storage-body">Body<textarea id="storageBody" rows="5" required>Record an instruction that can be kept offline.</textarea></label><button class="action primary" type="submit" data-core-bridge="browser-media-device-local-storage">Save new version</button><button id="storageRemove" class="action" type="button">Delete local data</button></form><section><h3>Version History</h3><ol id="storageVersions"></ol></section></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><figcaption class="gallery-caption"><strong>Presentation Space / GALLERY 03</strong></figcaption></figure>
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    const announce = message => { statusOutput.textContent = message; };
    /* 11DZ_CORE_SCRIPT_START:browser-media-device-local-storage */
const storageKey='browser-media-device-local-storage-presentation-room:versions';const storageMemory=[];let storageAvailable=true;function readStorage(){try{return JSON.parse(localStorage.getItem(storageKey)||'[]');}catch{storageAvailable=false;return storageMemory;}}function writeStorage(items){if(storageAvailable){try{localStorage.setItem(storageKey,JSON.stringify(items));return;}catch{storageAvailable=false;}}storageMemory.splice(0,storageMemory.length,...items);}function renderStorage(){const items=readStorage();document.querySelector('#storageMode').textContent=storageAvailable?'Persistent storage available · '+items.length+' versions':'Restricted environment · in-page memory '+items.length+' versions';document.querySelector('#storageVersions').replaceChildren(...items.map(entry=>{const item=document.createElement('li');const title=document.createElement('strong');const meta=document.createElement('small');title.textContent=entry.title;meta.textContent=entry.tag+' · '+entry.length+' Characters';item.append(title,meta);return item;}));}document.querySelector('#storageForm').addEventListener('submit',event=>{event.preventDefault();const items=readStorage();items.unshift({title:document.querySelector('#storageTitle').value.trim(),tag:document.querySelector('#storageTag').value,length:document.querySelector('#storageBody').value.trim().length,at:Date.now()});writeStorage(items.slice(0,6));renderStorage();announce('Offline note saved as a new version');});document.querySelector('#storageRemove').addEventListener('click',()=>{writeStorage([]);if(storageAvailable){try{localStorage.removeItem(storageKey);}catch{storageAvailable=false;}}renderStorage();announce('Local data for this case has been deleted');});renderStorage();
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workflowBridgeReset();
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