Making a variable element from existing element / querySelector doesn't accept Variables

Question

Im trying to select a child div from an array with the variable x

This is only a sketch to illustrate what I'm trying to do:

var x= 0;
 trackN = document.querySelector( .track :nth-child(x))

But querySelector doesn't accept variables.

I don't have ids on these objects (i could add them if this is the only option) nor jquery...

Answer 1

querySelector() accepts a string so you should be able to pass a variable...

document.querySelector('.track :nth-child('+x+')');