I need to implement Compare button as a link on product detail page.

What I trying to do:

<span><a class="btn-compare" onclick="popWin('<?php echo $_helper->getListUrl() ?>','compare','top:0,left:0,width=820,height=600,resizable=yes,scrollbars=yes')"><?php echo $this->__('Compare') ?></a><span>

Problem is $_helper->getListUrl() return strange link:

string 'my.dev/catalog/product_compare/index/uenc/aHR0cDovL2F0ZXguZGV2L2xpY2h0LWlua29vcC9iaW5uZW52ZXJsaWNodGluZy9wbGFmb25kLWluYm91dy90ZWtuaWx1eC03MzQ4NS5odG1s/' (length=160)

it's opening and closing in a second, there no products also.

Link must be my.dev/catalog/product_compate/index/.

Thanks.