Generic function to add a pair of enclosing "tags" to "script", then insert into "into" of "my_html"
add_tag_into(my_html, script, tag, into)html in a vector of strings; output from 'create_html'.
character string; script to add.
character string; html tags, e.g. div, span, script, style, h3.
character string; unique identifier of a line in the html. Element id is highly recommended.