shows event handler wrapping

example.js

var 
  // "appstate" object
  obj = {}, 
  // data-level onChange handler - doesn't deal w/ the dom.
  onChange = function(newValue){ obj.attr = newValue; },
  // start function that deals with the dom and calls the data-level event handler
  start = function(handler){
    $(".selector").on("change", function(e){
      e.preventDefault();
      handler(e.target.value);
    });
  };
start(onChange);