Domain check script

I have modified a simple Javascript and turned it into a tool that let you check how many pages (if any) you got listed in all the major search databases. The problem is that the search results opens in the same page so you have to use the browsers back button to return and check the next search engine. Is it possible to change the script so results opens up in a new window?

See the script at:
http://search-engine-secrets.net/domain_check.htm

Someone from another forum suggested this solution:

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Add

var params="width=450,height=250,toolbar=no"
var searchWin=window.open("","searchWin",params);

Then replace the last line with
searchWin.location.href=finalSearchString;
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This works, but the 2nd window opens right away when the page loads. Is there any way to make the result window pop up only when someone click on the search button?