countdown with mysql and form

edited:OK this should be correct, right?

hello first of all sry for my english, its not my first languague. i want to do a countdown that is not stopped when you close the site so i need a database, I started doing it in java with the examples of countdowns in the internet but I can't do it because I need to save the current countdown value in mysql and doing anything when its finished the example should be, you have a button in a form, you press it and you have a countdown of 5 minutes for example, this countdown value is saved in a database in mysql,when the countdown finish another action happen and you have the visual part of the site like at the beginning. Its my first post so i'm sorry if anything is not correct ty :D

thats what I have done I don't think that the way of writing the javascript into the php code is the correct one