if (loc_array[loc_array.length - 1] === 'index.html') {
   // do something
} else {
   // something else
}

In the event that your server serves the same file for "index.html" and "inDEX.htML" you can also use: .toLowerCase().

Though, you might want to consider doing this server-side if possible: it will be cleaner and work for people without JS.