Implementation of a Drag-and-Drop Captcha Using PHP and JavaScript

Motivated by curiosity after seeing several posts about drag‑captcha, the author implemented the first version of a drag‑and‑drop verification component as a learning exercise.

The source code is hosted at github.com/RLOFLS/drag-captcha , where readers can clone or fork the repository.

Visual examples demonstrate the captcha interface and its behavior during successful and failed attempts.

The core logic consists of generating rendering data on the server side and verifying the user's drag action on the client side.

API overview:

PHP side generate() – creates the data required for rendering the captcha (outputs dst and front). verify() – validates the user's drag result against the expected answer.

JavaScript side matchFunc() – triggers when the user drags the puzzle piece to attempt a match. render() – renders the drag‑captcha UI. matchSuccess() – applies the visual style for a successful match. matchFail() – applies the visual style for a failed match. destroy() – removes the drag‑captcha interface from the page.

Installation is straightforward with Composer: composer require rlofls/drag-captcha For a complete walkthrough and additional details, readers can click the “Read Original Article” link provided in the source.