Email Address Format Validator

WHAT IT DOES

Automatically detects and validates email address formats on web pages using comprehensive email syntax validation. The script scans page text for potential email addresses like user@domain.com, first.last@company.co.uk, or support@subdomain.example.org and validates them against RFC 5322-compliant format rules, domain structure requirements, and length restrictions. The panel displays detected email addresses with their status (Valid/Invalid/Unknown), domain, and a detailed breakdown of validation errors for invalid addresses. Valid addresses can be copied to clipboard with a single click, and results can be exported as text or JSON for audit and compliance purposes. Per-page validation results are saved per URL or custom identifier.

WHERE IT RUNS

Works on all websites (match pattern *://*/*), making it perfect for contact pages, directory listings, user profiles, customer portals, marketing databases, or any web page that displays email addresses. Each page gets its own independent validation results set, allowing you to scan and track email addresses across multiple contexts. Results are saved per page identifier, ensuring continuity across sessions and page reloads.

HOW TO USE

Install the script and the Email Address Format Validator appears in the panel. Click "Scan Page" to scan the current page for email addresses. The script detects potential email addresses and validates them against RFC 5322 format rules, domain structure, and length requirements. Each detected address is shown with a color-coded status indicator (green for valid, red for invalid), the full address, and a domain badge. Invalid addresses show a detailed breakdown of validation errors. Toggle validation rules for plus addressing, international domains, and strictness levels. Block specific domains to filter out unwanted addresses. Click any address to copy it to your clipboard. Use the export buttons to copy results as text or JSON for auditing. The script can auto-scan on page load if enabled.

REAL MECHANISM: RFC 5322-COMPLIANT EMAIL VALIDATION WITH CONFIGURABLE RULES AND ERROR REPORTING

This script uses a comprehensive email validation engine built around the RFC 5322 specification for email address syntax. The validateEmail() function performs multi-stage validation: empty check, length limits (local part ≤64, domain ≤255, total ≤254), @ symbol presence, local part character validation against allowed RFC 5322 characters (A-Z, a-z, 0-9, !#$%&'*+/=?^_`{|}~.-), local part dot rules (no consecutive dots, no leading/trailing dots), domain part structure (contains TLD, no consecutive dots, no leading/trailing dots, valid TLD characters), and part length limits (each part ≤63 chars). The strictness setting controls validation rigor: "loose" only blocks critical errors (missing @, empty parts), "standard" applies all rules with some tolerance for warnings, and "strict" enforces all rules exactly. Additional configurable rules include support for plus addressing (allowPlus), international domain support (allowInternational), and domain blocking (blockedDomains). Each validation failure generates a specific error message (e.g., "Local part exceeds 64 characters", "Domain contains consecutive dots", "TLD must be at least 2 characters"), which are displayed inline with invalid addresses. The extractEmails() function uses a regex pattern to identify candidates, then validates each one. Results are deduplicated using a Set. Each validated email is stored with its address, domain, local part, valid status, and errors array. The render function displays results with a color-coded status dot, a click-to-copy address, a domain badge, and a status label, with a collapsible error section for invalid addresses. Click-to-copy uses GM_setClipboard. Settings (strictness, allowPlus, allowInternational, autoScan, blockedDomains) are persisted via GM_setValue. All operations are reactive, with automatic persistence through saveEmailResults() and re-render.

THE PANEL

Drag the panel anywhere on screen by clicking and holding the header. It snaps to screen edges when released. Collapse it to a small bubble by clicking the minimize button, and expand it back by clicking the bubble. Resize the panel from any corner. Press Escape to close the configuration panel. Your position and size preferences are saved automatically per site.

PLEASE NOTE

This script requires the free BotGentz browser extension which provides the BGPanel framework and storage APIs. All data (detected emails, patterns, and page identifiers) is stored locally in your browser using GM_setValue and never sent anywhere. No analytics, no tracking, no external calls. The script only reads the current page content to detect email addresses and never accesses user data, passwords, or sensitive information. Validation is format-based only; the script does not send emails or verify mailbox existence.