Why not the collected works of JS code?

Why js code is not working, although via the console everything is clear, as in css gives the text.
And where you can read about the correct Assembly in this way?
"calc(20% -" + topP.clientWidth + "px)"
June 26th 19 at 14:20
2 answers
June 26th 19 at 14:22
Solution
and what should it be?
it is in the right place, which is available to topP?
css calc work only in JS - Ewell commented on June 26th 19 at 14:25
I do not understand. css expressions calc() have nothing to do with js, no - mina50 commented on June 26th 19 at 14:28
June 26th 19 at 14:24
Solution
Possible internal or external brackets need to change to single.

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