Is Highlighter for Google Chrome™ safe?

Highlighter lets users mark text on any active tab by injecting a local script that wraps selections in yellow highlight spans.

When the user clicks the extension icon, it injects a content script into the current tab that listens for mouse-up events and wraps any text selection in a yellow-highlighted span element. All processing happens locally in the browser; no text or page data is sent to any external server. On first install, the extension opens a welcome page at web-highlighter.pdfwork.com.