Javascript Developer to Fix Dvsa Slot Scanner Hold Mode Functionality

We are seeking an experienced Javascript developer to resolve a critical bug in our dvsa (uk driving test) slot scanner. The core issue lies within the 'hold mode' functionality, which allows continuous scanning of 'Previous Available' slots by holding down the arrow key. While this feature works flawlessly on fast internet connections, it consistently fails during peak hours or when the DVSA website experiences lag.

The problem stems from the scanner's current implementation, which relies on a fixed 800ms timer between clicks. This timer does not account for variable page load times. Consequently, during slow periods, the scanner attempts to click buttons that are either stale or not yet visible because the page has not finished loading between actions. This leads to the scanner breaking down and failing to find available slots.

The existing scanner has robust UI controls, accurate slot detection, and reliable reservation logic, all of which function correctly. The only component requiring a fix is the 'hold mode' for continuous scanning. The ideal solution will involve implementing a robust page load detection mechanism to ensure that the scanner waits for the page to fully render before proceeding with the next action, thereby making the continuous scanning reliable regardless of website performance. We need a developer who can diagnose and implement a resilient solution for this timing and page state issue.