Comic Book Marketplace Grade Comparison Overlay

WHAT IT DOES

Comic Book Marketplace Grade Comparison Overlay scans the current page for comic book listings, extracting titles, issue numbers, grades, prices, and seller information from marketplace pages (eBay, MyComicShop, etc.). The floating panel shows grade comparisons across multiple listings, highlighting the best value based on grade-to-price ratio. Visual grade indicators (CGC, CBCS, raw grades) with color-coded quality levels and price comparison bars make it easy to spot deals. Add custom grade assessments and notes to listings. Export grade comparison data as CSV or text for research. Price trends by grade are tracked, and overpriced and underpriced listings are highlighted.

WHERE IT RUNS

Works on any comic marketplace page, including eBay, MyComicShop, Heritage Auctions, ComicLink, and other comic selling platforms. The script detects comic listings using common selectors and can also fall back to general item cards. It works best on pages with structured listings containing grade and price information.

HOW TO USE

The panel displays all detected comic listings with their grades, prices, and seller information. Click "Scan Listings" to detect comics from the current page. Each listing shows its grade (with icon), price, value score, and seller. The best value listing is highlighted in green with a star badge. Click "Assess" to add a custom grade assessment and notes to any listing. Export the data as text for research or offline reference. The panel shows grade type indicators (CGC, CBCS, Raw) and color-coded quality levels from Mint to Good.

MECHANISM — GRADE PARSING WITH VALUE SCORE CALCULATION

The script extracts comic listings using a multi-strategy approach. It first attempts to find listing containers using common marketplace selectors (.listing, .item, .product). From each container, it extracts title, grade text, price, and seller using targeted sub-selectors. The grade parser handles numeric grades (9.8, 9.6, etc.) and detects grade types (CGC, CBCS, Raw). The value score is calculated as grade / price, providing a normalized measure of value per dollar. Higher scores indicate better value. The best value listing is automatically identified and highlighted. Grade colors range from green (mint) to gray (good), providing visual quality indicators.

THE PANEL

The floating panel is fully draggable and remembers its position per domain. Click the minimize button to collapse it to a small bubble, or press Escape to hide it. The panel automatically adjusts to different screen sizes and can be resized to show more content. All settings and grade assessments are saved per domain. The panel integrates smoothly with any page layout using the BGPanel framework, maintaining clean separation from page content.

PLEASE NOTE

This script requires the free BotGentz extension to run. It does not send any data to external servers; all extracted comic data and grade assessments remain entirely local to your browser using GM_setValue. The script never reads password fields, hidden inputs, or file inputs. It stores only comic titles, grades, prices, seller information, and user-entered assessments from publicly visible page content. Listing detection depends on the page structure; if comics are not detected, use the "Scan Listings" button to refresh extraction. Data persists across browser sessions and is isolated per browser profile.