Urgent Javascript Website Repair: Resolve Startup Failure

Our JavaScript-based website is currently experiencing a critical issue where it fails to start up or load correctly. We are seeking an experienced web developer to diagnose and resolve this problem promptly. The ideal freelancer will have strong debugging skills in JavaScript and be able to identify the root cause, which could range from front-end code errors to back-end configuration issues or dependency conflicts. The goal is to restore full functionality to the website as quickly as possible. Please outline your approach to troubleshooting and your relevant experience with similar JavaScript website repair projects.