Safari browser has an option for enabling or disabling the pop up window blocker. This can be done using the General Settings menu available at the top right hand corner of the browser.
Click the drop down arrow next to the General Settings menu option. From the list of available menu, navigate to Block Pop-Up Windows menu option and un tick the option. This would turn off the Pop Up Windows blocker in Safari.
The Windows short cut key for to enable or disable Pop-Up Windows blocker is Ctrl + Shift + K