I have a link like this:
$contact_url = "rentals_id >" . "Contact" . "";
<
I can't comment on Esben Skov Pedersen's answer directly, but using the following notation for links:
Click here
In Internet Explorer, the new browser window appears, but the current window navigates to a page which says "[Object]". To avoid this, simple put a "void(0)" behind the JavaScript function.
Source: https://support.microsoft.com/en-us/kb/257321