Company Directory Single Page Application

This is a Single Page Application I built to allow a management team to keep track of staff contact details, their departments, and their locations.
I used Javascript to make a fast search, sort, and filter form. Bootstrap was used and modified for a clean look on the frontend, and I also used vanilla CSS to create dynamic charts that display staff and department distribution.
PHP routines were used on the backend to fetch staff data from a MySQL database using PDO.
Rigorous validation was done using both the frontend Javascript and then backend PHP to ensure no records with dependencies could be deleted, and to protect against first and second order SQL injections.