Wrong syntax again

Hello, this time I have a problem with replacing the path to the file with var.

i get path from my main.js

var csInterface = new CSInterface();  
var extensionRoot = csInterface.getSystemPath(SystemPath.EXTENSION) + "/jsx/custom.jsx";  
csInterface.evalScript("selectedPath('" + extensionRoot + "')");

In hostscript.jsx :

function selectedPath(extensionRoot) {  
pathOK = extensionRoot;
alert(pathOK);
 }

alert

= C:/Program Files (x86)/Common Files/Adobe/CEP/extensions/PREPRESS_2019/jsx/custom.jsx

And this hostscript.jsx work:

function selectedPath(extensionRoot) {  
pathOK = extensionRoot;
alert(pathOK);
 }
#include 'C:/Program Files (x86)/Common Files/Adobe/CEP/extensions/PREPRESS_2019/jsx/custom.jsx'

and this one does not:

function selectedPath(extensionRoot) {  
pathOK = extensionRoot;
alert(pathOK);
 }
#include pathOK;

How to change it to work ?