How to Handle Button Click Events in jQuery?

$('#btnSubmit').click(function(){
    alert("button");
});

or

//Use this code if button is appended in the DOM
$(document).on('click','#btnSubmit',function(){
    alert("button");
});

See documentation for more information:
https://api.jquery.com/click/

$(document).ready(function(){

     $('your selector').bind("click",function(){
            // your statements;
     });

     // you can use the above or the one shown below

     $('your selector').click(function(e){
         e.preventDefault();
         // your statements;
     });


});

You have to put the event handler in the $(document).ready() event:

$(document).ready(function() {
    $("#btnSubmit").click(function(){
        alert("button");
    }); 
});