check if input file filed is empty jquery

Question

I have a form with a file input and I want to check if it is empty when the form is submitted.

I have this code:

$('form#new_comment').submit(function(e) {
   var $this = $(this);
   var $input =  $this.find('input').val();
 if($($input == '')) {
   alert ("you must choose a image");
   return false; 
   e.preventDefault(); 
  }    
});  

But it always says you must choose a image, even when I have chosen an image.

Where is the problem?

Answer 1

Change:

if($($input == '')) {

To:

if($input == '') {

Since it is simple variable that holds text, you don't need to use jQuery function over it again.