Hi,
Facebook does no more actively support the Share button. It should still work, but should no more be used in new projects.
So the replacement for the Share Button is the Like-Button:
https://developers.facebook.com/docs/reference/plugins/like/[
^]
To implement a Like-Button, you just have to add the following to your page:
<div id="fb-root"></div>
<script src="http://connect.facebook.net/en_US/all.js#xfbml=1"></script>
<fb:like href="http://www.codeproject.com/" send="true" width="450" show_faces="true" font=""></fb:like>
This code was directly copied from the above link, the page can generate the code for you.
Hope this helps.
Best regards and happy coding,
Stops