I have a form on my website that I want to ensure each client only submits once per year.
To do this, I would like to save the client's id # and the current year to a .txt file on my server when they submit the form.
When the form is submitted, I also need to check the current contents of that file to ensure their id has not already been recorded, and display a message if they have already submitted the form that year.
I believe I need to use PHP to do this, but I'm brand new to PHP and I'm also not very experienced with jQuery. Any assistance would be much appreciated!
Using a simple database would be much better, because it will be easier to retrieve the stored data later on. There are more than enough tutorials if youre not familiar with databases (use mysql database if you have few experience with databases).
If you use a database you can also store the submitted data from the form very easy.
As Dan already said, first learn PHP and database connects and querys and then jQuery (which you dont need for putting data from a form into a database, but with ajax its cooler (you dont even need jQuery for ajax, vanilla javascript can also do that for you) ;) ).
Just google everything, there are more than enough tutorials online.
If you don't want to use a database, probably the simplest option will be to rename the received file with clientId-currentYear when you put it on the server.
For example, when a user submits a file for client 12345, you will have to check if a file 12345-2018 already exist. If it doesn't exist, you can create it, if not, you send your message to the user.
This is going to be easier to manage than a text file or a database if your programming level is low.