Someone thought that the problems with hidden fields were too great, so they decided that a way to preserve data locally on the users machine would be a good idea.
They made cookies, which are sent in an optional header of the HTTP messages. The data is stored with an identifier and the data which is saved, then next time the user visits the data is extracted and used.
Cookies work only for 512 entries (sites in this case) and the size of each entry is limited. (I'll get back to that, in the future.)
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