Placeholders are not replaced

Question

I am experimenting with the package http/template.
I have also already managed that e.g. the header, footer, navbar and so on were included in the base templ

Answer 1

You're not passing any data to the child templates. Per the docs:

{{template "name"}}
    The template with the specified name is executed with nil data.

{{template "name" pipeline}}
    The template with the specified name is executed with dot set
    to the value of the pipeline.