Jquery button click detection

I have a div class in my html file named 'btn'. In my Javascript file I use jquery to detect clicks on that btn. When the jquery function to detect clicks is written in the global scope,the function doesn't work,but when I put it inside another function and call it using developer tool console,it works. Can somebody help me out with this please?

Code for reference-

$(".btn").click(function() {
   console.log('Clicked');
}

This below code works-

function clickDetection(){
   $(".btn").click(function() {
   console.log('Clicked');
   }
}