Input scanner

gistfile1.js

$(document).ready(function(){

  function Scanner(el) {
    this.robot = false;
    this.count = 0;
    this.tick = 0;
    this.total = 0;
    this.avg = 0;
    this.scanThreshold = 10;
    this.minChars = 25;
    this.callback = null;
    this.el = $('#'+el);
    this.init();
  }
  
  Scanner.prototype.init = function() {
    var self = this;
    this.el.on('keyup', function(e){ self.scan(); });
    this.el.on('focus', function(e){ self.reset(); });
    this.el.on('blur', function(e){ self.reset(); });
  }
  
  Scanner.prototype.scan = function() {
    var d = new Date();
    var newTick = d.getTime();
    var diff = newTick - this.tick;
    this.count++;
    
    if(this.el.val() == '') {
      this.reset();
    }
    if(this.tick != 0) {
      this.total += diff;
      this.avg = this.total / this.count;
    }
    this.tick = newTick;       
    if(this.avg < this.scanThreshold && this.count >= this.minChars) {
      this.robot = true;
      this.complete();
    }

    //console.log('avg keystroke duration=' + this.avg);
    //console.log('robot=' + this.robot);
  };
  
  Scanner.prototype.on = function(action, fn) {
    // only one action currently
    this.callback = fn;
  }
  
  Scanner.prototype.complete = function() {
    if(this.callback != null)
      this.callback();
  };
  
  Scanner.prototype.reset = function() {
    this.count=this.tick=this.total=this.avg=0;
  };
 
  var scanner = new Scanner('box');
  
});