Auto Expanding Textareas

WHAT IT DOES

Auto Expanding Textareas automatically grows textarea elements to fit their content as you type, eliminating the need to scroll within small text boxes. Each textarea expands smoothly from its minimum height up to a configurable maximum height, then scrolls once the limit is reached. The tool works with any textarea on the page—comment boxes, message fields, code editors, and form inputs all benefit from automatic height adjustment. You can set minimum and maximum height limits, enable or disable animation, and the tool remembers the height of each field so your preferences persist across page loads.

WHERE IT RUNS

The extension runs entirely within your browser's local environment using the BotGentz framework. All textarea detection, height calculation, and DOM manipulation occur on your machine without any network requests. No text content, height data, or user activity is ever transmitted, uploaded, or stored externally. The tool works on any website and respects the browser's security boundaries, operating within the isolated extension sandbox. Textarea resizing uses the browser's native scrollHeight property and CSS height manipulation.

HOW TO USE

Click the extension toolbar icon to open the Auto Expanding Textareas panel. The tool works automatically—every textarea on the page expands as you type. Click "Refresh Textareas" to detect dynamically added textarea elements. Click "Reset All" to collapse all textareas back to their minimum height. Toggle "Auto expand" to enable or disable the expansion feature. Toggle "Animate height changes" to control whether height changes are smooth or instant. Toggle "Trigger on paste" to expand textareas when content is pasted in. Toggle "Remember per field" to save the height of each textarea across page loads. Adjust the "Min height" setting (20-200px) to control the starting height. Adjust the "Max height" setting (50-1000px) to control the maximum height before scrolling. The panel shows the current settings and provides clear controls for customization.

THE AUTO-EXPAND ENGINE — WHY IT WORKS

Most auto-expanding textareas rely on simple scrollHeight readings but fail to account for padding, borders, or animation timing. This tool uses a precise calculation: it sets the textarea height to "auto" to get the true content height, then reads scrollHeight, which includes the content plus padding and borders. The target height is clamped between minHeight and maxHeight, with overflow-y toggled to "hidden" below the max and "auto" above it. The tool also stores the previous height to enable smooth transitions. The per-field memory stores the last height of each textarea using GM_setValue with a unique identifier (id, name, or generated ID), so the height is restored on page reload. The animation uses CSS transitions with a 0.15s ease timing, controlled by the toggle. The paste trigger adds a small delay (10ms) to allow the content to render before reading scrollHeight. This combination of precise measurement, animation control, and persistence provides a polished, reliable auto-expanding experience.

THE PANEL

The Auto Expanding Textareas panel is fully draggable by its title bar and remembers its position on screen per website. It snaps to the edges of your browser window for clean alignment. Collapse the panel to a compact icon strip using the minimize button, restoring it with a single click. Resize the panel by dragging any edge or corner; the controls and options adjust proportionally. Press the Escape key to close the panel instantly. The panel maintains independent state for each browser tab, allowing you to manage textarea expansion in multiple tabs simultaneously.

PLEASE NOTE

This extension requires the free BotGentz extension framework to be installed and enabled. The tool works with standard HTML textarea elements; rich text editors and custom input fields may not be supported. Some websites may set fixed heights on textareas that override the auto-expand behavior. The tool stores height data per field; clearing your browser data will remove saved states. All textarea data is processed locally and is never transmitted, logged, or shared. The extension requests no network permissions and functions entirely offline. The source code is fully auditable and available for review.