html - How to generate and where to store unique id for client? -

i have static website (without , backend) form. when user submit's form make jsonp request google apps script. gas handles request , saves form data goggle spreadsheet following structure:

      name      |     age     |     city      ------------------------------------       eric      |      23     |     nyc 

now need store id unique each user , store this:

      clientid  |     name      |     age     |     city      ---------------------------------------------------       dhs3kwhe  |     eric      |      23     |     nyc 

i don't restrictions clientid format single clientid unique client.

this similar session id , cool use because don't have backend can't generate one.

what is best way resolve issue?

edit:

let me little explain problem. need not generate unique id generate algorithms. need generate clientid each user. user a fills , submit form , generate him clientid jshhsd3. next time user a fills , submit form has same id jshhsd3.

another user b have own clientidwhen submit form.

session.getactiveuser().getemail() give unique google email address each user.

to store each id? try:

var userid = session.getactiveuser().getemail(); var scriptproperties = propertiesservice.getscriptproperties();     scriptproperties.setproperty('username', userid);