PHP question (opening URLs in separate tabs)

[scythe]

I hope it's OK that I sneak in a PHP question here.

Let's say I have an input box and a submit button. I type something in the box and hit submit and get redirected to dosearch.php.

In dosearch.php, I create two strings and add what ever I put in to the box at the end.
For example:
http://www.google.se/search?q=myinput
http://www.altavista.com/web/results?q=myinput

My question is: can I automatically open these URLs in separate tabs as if I were using target="_blank" (in Mozilla).

Thank you in advance.
- Daniel