windowIncludes is a case-sensitive function that is used to check if the current base url matches the
list of supplied urls. Since index pages can either be empty (i.e "") or "index", a frontslash ("/") can be used to denote
an index page.
if( windowIncludes('some/url') ){
// current url is "some/url"
}
$validUrls = ['some/url1', 'some/url2'];
if( windowIncludes($validUrl) ){
// current url is in accepted urls
}