You need to understand how popup blockers work and which types of popup they block.
From MSDN,
The Pop-up Blocker blocks script-initiated pop-up windows that are created by the following methods, without the user clicking a link.
The Pop-up Blocker does not block pop-up windows that open as a direct result of a user action. A user-initiated action includes clicking a page element or tabbing to a link and then pressing ENTER.
So if a popup is created by some user action, browsers won't block it under default settings. So use this technique.
BTW, read this MSDN link for better understanding of the concept -
About the Pop-up Blocker[
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Hope this helps! :thumbsup: