Simple two-way data-binding

TwoWayDataBinding.js

var Field = function(selector){
  
  var el = document.querySelector(selector),
      callback;

  this.get = function() {
    return el.value;
  };
  
  this.set = function(val) {
    el.value = val;
  };
 
  this.handler = function(_callback) {
    callback = _callback;
  };
 
  el.onchange = el.oninput = el.onpaste = function(){
    callback(el.value);
  };
};

var input = new Field("input");

input.set("Sanya");
input.handler(console.log);
input.get();