Passing in function to the .on function

Passing in function to the .on function

Hey Guys. I am a little bit confused when passing in functions in the .on parameter. Why does the function that we pass in doesn't include an opening and closing parentheses??

For example i pass the function highlighted. (Got the code from a tutorial btw) and the function takes no parentheses. Doesn't jquery need that in order to tell if its a function. Why in other parts of the code we need to include parentheses in this we don't. Thanks

  1.    <script type="text/javascript">
          var eventTarget = $("#evtTarget")  ;
             
        $(function() {
              
           eventTarget.on("mouseenter mouseleave", highlighted); // No parentheses when calling the function
           eventTarget.click("click", function() {
               eventTarget.off("mouseenter mouseleave", highlighted);

           });
                      
            });
           
            function highlighted () {
               eventTarget.toggleClass("highlighted");
            }