If use «File > Save As > HTML» links «in» and «out» are lost
How to save a document without loss of these lines/links?
UPD: You can write in the css rules (:after { content: "In[i]:="; }
) for .Input
and .Output
.
Example: http://wolframo.tk/nb/1s8efpc546a9986b3618.html
Application: https://github.com/latur/Wolframo
But it's not quite what I wanted