How to write for "ctrl + F" or some other ctrl or shift combos?

Hello.

What title says.

I know this seem simple but won't work for me by some reasons.

I tried to use variable to keep track of "key is down, key is pressed".

So I was wondering if anyone have done a elegant solution for these needs?

commands like shift and control are complicated because if they are used in the browser they can activate its functions, mainly the control, however if you put a variable that receives this command, like giving a letter to each key and concatenating them, it might work, however, this variable must be equal to empty after being used

What doesn’t work about it? Doesn’t this work?

On f key pressed
Control key is down
— do something. 

Ok now it works. I must have put the events in wrong place before.

Thanks folks!

Appreciated I also got my solution Thanks everyone....