What’s new in ColdCode.

JavaScript runs as a real page script

The JavaScript editor’s code runs as its own top-level script: const and let declarations are visible to inline handlers like onclick="greet()", 'use strict' works, a trailing // comment no longer breaks the whole script, and errors point at the editor’s own line numbers.

Safer saving

• Undo can no longer empty a freshly loaded editor.
• An idle second tab no longer overwrites newer work from another tab.
• Emptied editors stay empty after a reload.
• Blocked or full browser storage is reported instead of breaking the app.

Full-code layout keeps your document

The full-code document is saved and previewed exactly as written, including attributes on <html> and <body>, script types and script positions.

Infinite-loop recovery

If a run never finished, for example an infinite loop that froze the tab, it isn’t run again on the next start, and Auto-run is paused until you press Run.

Preview fixes

• Forms in the preview can be submitted.
• JSON-LD, template and module scripts are no longer merged into the JavaScript.
• Stale console lines from the previous run are dropped.
• The preview no longer adds styles of its own, so it matches downloaded files.

Import and export fixes

• A ZIP export can be imported again without nesting documents or loading files twice.
• Multi-file import says which files it skipped.

Interface fixes

• Ctrl/Cmd + Enter in an editor only runs the code.
• The theme icon keeps updating.
• Dialogs return focus to the menu that opened them.
• Console colors meet WCAG AA contrast.
• Dark mode applies before the first paint.
• Pane sizes survive layout changes.

Integrity

Split.js, Lucide and JSZip are loaded with Subresource Integrity hashes.

Accessible controls

Editors are named, hidden file inputs no longer appear to assistive technology, status messages are announced, and the theme toggle always describes its next action.

Under the hood

New browser tests cover layouts, small screens, saving, console isolation, dialog focus and theme accessibility, and dependencies are up to date.

Reliability

Every CDN dependency is pinned to an exact version, and a visible error banner appears if the app ever fails to load.

True autosave

Code is saved on every change, even with Auto-run off, and flushed when the tab is hidden or closed.

Sandboxed preview

The preview no longer shares the app’s origin, so snippets can’t clobber ColdCode’s saved data. localStorage and sessionStorage in snippets use an in-memory stand-in that resets on each run.

<head> preservation

Titles, meta tags and links survive full-code and split conversions, imports, saves and downloads.

Layout fixes

Bottom and right layouts put the drag handle between the panes and drag the intuitive way, and layouts adapt when the window crosses the mobile breakpoint.

Console upgrades

Uncaught errors and unhandled promise rejections are captured, not just console.* calls, and output is capped at 500 entries so runaway loops can’t hang the page.

Robustness

Code containing </script> or </style> no longer breaks the preview, and menus and dialogs gained ARIA roles, keyboard navigation and focus management.

CodeMirror 6

The editor moved from CodeMirror 5 to the modern CodeMirror 6 framework.

Console output panel

See console.log, error, warn and info output from your code.

Better performance

Virtual rendering for large documents.

Improved mobile support

Better touch handling and on-screen keyboard support.

Modern architecture

ES modules with import maps, and still no build step.

One Dark theme

The dark theme from the CodeMirror team.