Stop geURL Command

I have a mailing post script that executes a url to sign up on a mailing list

getURL(“http://app.campaignmonitor.com/api/api.asmx/Subscriber.Add?ApiKey=b6eaddb23e91f8f6aaabbfa6d4c5 81abde851343&ListID=50578&Email=” + _parent.email + “&Name=” + _parent.namef + “”, “_blank”,“POST”);

A window opens up that I don’t want to open, I want to kill the window before it opens, is there a way to do it?