HTML page that save its content, replacing the HTML file itself

I've to create a html page that auto-save its content.

This page is just a report of the activities of 4 days, that should be updated by some user.

This page will be used just for 3/4 days (Go live summary status page, and this say i all).. So I don't wanna lose time with backend, but I wanna do something like a trick just on client side, Javascript and HTML.

What I would like to do:

A user access to the page, this page is published on our internal server, update the status of the task and save the page! I thought to do this in two ways:

• Any time I press the save button it just replace the old html content with the new one (replacing the html file itself)
• Save the content in a plan file that will be loaded everytime the page is used, this second option obviously costs a lot of more work..

Any suggestion? I meant, is there something that help me doing this in just few time? I've about 2 days to finish this :(

UPDATE: Guys maybe i'm not explaining myself so good, am i thinking so wrong if i suppose just something like this:

Javascript function that when you click the save button replace the old html server file with the new one containing the row updated...

Easy easy easy...! I'm a backend developer.. not a lot of experience with beautiful styled front end pages :)

UPDATE: By your answer i'm assuming that is NO WAY to do this, without a backend side logic, even if light one, but its not possible to achieve this just with a client side scripting.. I already thought at this, but i was hoping there is some kind of trick that allows to do this without place anything on the server side.. :(