# Cite a website with date

I'm trying to create a website bibliography, but the urldate is not being shown, only the year when the website was last update.

\documentclass{article}

\usepackage[sorting=nyt,style=authoryear, backend=bibtex8]{biblatex}

\DeclareCiteCommand{\parencite}
{\ifentrytype{online}{\bibopenparen}{\bibopenbracket}
\usebibmacro{prenote}}
{\usebibmacro{citeindex}
\usebibmacro{cite}}
{\multicitedelim}
{\usebibmacro{postnote}
\ifentrytype{online}{\bibcloseparen}{\bibclosebracket}}

\begin{filecontents}{\Literature.bib}
@online{Wikipedia.27.02.2017,
author = {Wikipedia, the free encyclopedia},
year = {2017},
title = {MALDI-TOF},
url = {https://de.wikipedia.org/wiki/MALDI-TOF},
urldate = {02.06.2017}
}

\begin{document}

\parencite{Wikipedia.27.02.2017}

\newpage
\printbibliography[heading=bibintoc,title={ Internet Sources },type=online]

\end{document}

• You must enter the date in the right format: urldate={2017-06-02} Jun 21 '17 at 8:46
• Your MWE doesn't compile btw: undefined \fancyhead, undefined \Literature, missing \end{filecontents}… you should always test your MWE before posting it! Jun 21 '17 at 9:17
• Jun 21 '17 at 9:22

You need to specify the date in biblatex's date fields in a certain way. From the manual:
Date fields such as the default data model dates date, origdate, eventdate, and urldate adhere to EDTF (Extended Date/Time Format) specification levels 0 and 1.
This will most times mean yyyy-mm-dd, so in your case:
urldate={2017-06-02}