Serious problems saving and loading a simple string from a canvas object

I have several canvas items to display when a creature is killed. The final to display in the column is a ExperiencesText. I keep a running total of the kills and multiple them by a .003 and that is displayed as experience. All I want to do is get that value (string) , save it when the webgl game is closed and load it when it is opened for each individual player. I have a website that i use to host a temporary representation of the game. I use php and mysql to login to the website. it would be nice to store that data in a field I have in that mysql database called String... but even player prefs would be ok for such a simple storage. I have looked everywhere and no solution fits. so simple ... that's why Help?
Thanks