Une vente solidaire est organisée pour leur venir en aide. A random copy-paste from the web. Anyway here is the mandatory French localization.
The localization is done with $.tools.dateinput.localize before the dateinput initialization as follows:
For maximum safety we suggest that you encode special characters with the corresponding HTML entities. There are many lists on the web. I used this one.
You'll use the lang option for dateinput to enable the new language. Note that this value can be dynamically set depending on the user's location on the globe.
// dateinput initialization. the language is specified with lang- option
$(":date").dateinput({
lang: 'ja',
format: 'yyyy "年" mmmm dd "日" dddd',
offset: [30, 0]
});