Code open the external links in new tab, or new window

Hi all,
I have a problem to open an add in my app in new tab, it is opening in
the same tab of my site.

in my view I have added
<%= show_industry_sponsor(@community.industry) %>

and in application_helper.rb
def show_industry_sponsor(industry)

 return "<a href='http://www.someurl.com'

onclick=‘window.open(this.href,’_blank’);return false;’ >"

end

please help me out… its urgent.