The easiest way to check as to whether or not your jQuery selector is returning a value is to remember that the selector is simply returning an array of jQuery objects. If no matching elements are found it simply returns an empty array.
Which of course then means that you can either check the length or size() of the returned value to ensure that it is greater than 0, indicating that your selector has successfully matched on your search request.
In other words:
if $(‘#selectMyElement’).length > 0 returns true, then you know you’ve got a hit!