You can't use target= as an attribute of a *BUTTON*.
target is only valid in A, AREA, BASE, FORM, and LINK elements.
That is, something like:
And you don't *HAVE* to use _blank. In fact, if you want to purposely reuse an existing window, just use a specific name. If no window of that name exists, then a new one is created. But if such a window already exists, then the give url will populate it.
<input class="button space" type="button" value="View Photos on ebby.com"
I do that all the time with image popups on my own site, for example:
<input type=button value="show me"
onclick="window.open('/images/foo.jpg', 'PICTURE', 'width=500,height=300');">