Text editor in HTML page for Ethernet Shield ?


I have an Arduino Mega 2560 with Ethernet Shield. My Arduino runs a webpage with a form. I use that to add a single line of text to a file on the SD card. I pre-fill the form with the date and time of the computer. The beginning of each stored line is the date and time, which is very handy to keep track of battery voltages and so.

Now I would like a full text editor on a webpage that will be written to the SD card. Did someone make something like this ?

The only thing that I can think of, is pre-fill the form with the text file and send the complete form contents to the Arduino to store it. I don't know if that will work with large files.