Submit button validation to 3 selected li only

Question

How to check if the selected modules are 3 or less than 3. When less than 3 prompt alert please select 3 modules. If selected 3 modules, prompt thank you for submission.
$('#selectModule').click(function(){
if ('#moduleList li:gt(2)' == 3)
{
alert("Thank you. Your selected modules have been submitted.");
}
else
{
alert("Please select 3 modules for submission");
}
});

Answer 1

I wud have a loop before
With an if statement and counter
If selected moduleList++
Then check if that value is greater than 3