BibLaTeX: How to remove dot in modified field format

Question

when citing online sources, I have to have [online] printed after title, so it would look like this:

I tried adding following line into biblatex.cfg:

\DeclareFieldFormat[www,online]{title}{#1\space\printtext{[online]}\addperiod}

which gave me this:

but I cannot find out how to remove the dot between title and [online]. Thanks for any help.

EDIT: Here is the MWE, I hope I did it right:

This is the tex file:

\documentclass[twoside,12pt]{report}

\usepackage[czech]{babel}

\usepackage[backend=biber,
natbib=true,
url=false, 
doi=true,
eprint=false,
maxnames=3,
minnames=2,
doi=false,
urldate=edtf,
giveninits=true,
sorting=none,
sortcites=true]{biblatex}
\addbibresource{ref.bib}

\usepackage[unicode=true,
bookmarks=true,
colorlinks=true,
breaklinks=true,
a4paper]{hyperref} 

\begin{document}

example \cite{paleywww}

\printbibliography

\end{document}

This is file ref.bib:

@WWW{paleywww,
    author  = {Dror Paley},
    title   = {History of implantable leg lenthening},
    url     = {http://www.mheresearchfoundation.org/files/Implantable_limb_lengthening.pdf},
    urldate = {2017-05-05},
}

Answer 1

Use

\DeclareFieldFormat[online]{title}{#1\setunit{\space}\printtext{[online]}}

Since you use \printtext, you were getting the punctuation from the punctuation tracker, with \setunit{\space} you make that a space.