Formats currency input and provides a method from extracting the amount (in fractional currency units - i.e. in cents/pennies) http://jsfiddle.net/7g26x0uL/155/

currencyField.js

$.widget( "nmk.currencyField", {
   
   // Default options.
   options: {
      decimalPlaces: 2,
      decimalSeperator: ".",
      thousandSeperator: ",",
   },
    
  _create: function() {

    if(this.options.decimalSeperator === this.options.thousandSeperator){
       this.options.thousandSeperator = null;
    }
    
    if(this.options.decimalPlaces === 0){
       this.options.decimalSeperator = null;
    }
    
	this.element.on('keydown', $.proxy(function(evt){
  
      var char = evt.key;
      var value = $(evt.target).val();
	
      if (
        // ALlow delete, backspace, tab, escape, enter and workaround for Samsung 
        $.inArray(evt.which, [46, 8, 9, 27, 13, 229]) !== -1 ||
        // Allow: Ctrl+A/V/X, Command+A/V/X
        ($.inArray(evt.which, [65, 86, 88]) && (evt.ctrlKey === true || evt.metaKey === true)) || 
        // Allow: home, end, left, right, down, up
        (evt.which >= 35 && evt.which <= 40) ||
        // Allow thousand seperator
        (this.options.thousandSeperator && char === this.options.thousandSeperator)) {
        return;
      }

      if(char === this.options.decimalSeperator){
        return value.indexOf(this.options.decimalSeperator) === -1;
      }

      // Abort if not a number
      if ((evt.shiftKey || (evt.keyCode < 48 || evt.keyCode > 57)) && (evt.keyCode < 96 || evt.keyCode > 105)) {
        evt.preventDefault();
      }
 
      // Ensure the maximum number of decimal places is not exceeded
      var caratPos = evt.target.selectionStart;
      var dotPos = value.indexOf(this.options.decimalSeperator);
      var parts = value.split(this.options.decimalSeperator);
      if( caratPos > dotPos && dotPos > -1 && (parts[1].length > this.options.decimalPlaces - 1)){
        return false;
      }
       
    },this));

    this.element.on('paste', $.proxy(function(event){
      event.preventDefault();
      var value = event.originalEvent.clipboardData.getData('text/plain');
      this.element.val(this._formatAmount(this._parseAmount(value)));
    },this)); 

    this.element.on('blur', $.proxy(function(){
      this.element.val(this.formattedAmount(this.getAmount()));
    },this));     
  },
    
  getAmount: function(){
     return this._parseAmount(this.element.val());
  },
  
  formattedAmount: function(){
     return this._formatAmount(this.getAmount());
  },

  _parseAmount: function(value){
    if(!value){
        return 0;
    }
    var numeric = value.replace(new RegExp('[^0-9'+this.options.decimalSeperator+']','g'), '');

    var regex = new RegExp('^(\\d+(?:'+this.options.decimalSeperator+'\\d{0,'+this.options.decimalPlaces+'})?).*$','g');
    var parts = numeric.replace(regex,"$1").split(this.options.decimalSeperator);
      
    var integer = parseInt(parts[0],10) * Math.pow(10, this.options.decimalPlaces);
    if(parts.length > 1){
       integer += parseInt(this._pad(parts[1],this.options.decimalPlaces, 'right').slice(0, this.options.decimalPlaces),10);
    }
    
    return integer;
  },
    
  _formatAmount: function(amountInFractionalUnits){
    var parts;
    if(this.options.decimalPlaces){
      var regex = new RegExp('^(\\d+)(\\d{'+this.options.decimalPlaces+'})$');
      var parts = this._pad(amountInFractionalUnits, this.options.decimalPlaces + 1, 'left')
                       .replace(regex,"$1"+this.options.decimalSeperator+"$2")
                       .split(this.options.decimalSeperator);
    } else {
      parts = [amountInFractionalUnits];
    }
  
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(parts[0])) {
      parts[0] = parts[0].replace(rgx, '$1' + this.options.thousandSeperator + '$2');
    }
    return this.options.decimalSeperator && parts.length > 1 ? parts[0] + this.options.decimalSeperator + parts[1] : parts[0];
  },
  
  _pad: function(string, length, type){
     var n = length - (""+string).length;
     if(n > 0) {
        var padding = (new Array(n+1).join("0"));
        string = type === 'left' ? padding + string : string + padding;
     }    
     return string+"";
  }
});

demo.html

<input data-thousand="," data-decimal="." data-decimalplaces="2" id="input" type="text"/>

<p id="render"></p>
<p id="render2"></p>

demo.js

$('#input').currencyField({
   decimalPlaces: $('#input').data('decimalplaces'),
   decimalSeperator: $('#input').data('decimalseperator'),
   thousandSeperator: $('#input').data('thousandseperator')
});

$('#input').on('change blur', function(event){
    $('#render').text($(this).currencyField('getAmount'));
    $('#render2').text($(this).currencyField('formattedAmount'));
});