У вашего броузера проблема в совместимости с HTML5
Casio SE-G1 Flashing 0 on screen means that you are at the language setting part of the cash register initialisation. To set the register to English language press 0 then press CA/AMT/TEND and follow the on screen prompts for entering the date and time.
For more technical assistance on the SE-G1 please visit: https://www.cashregisters-uk.co.uk/acatalog/SEG1.html