var date_diff_indays = function(date1, date2) {  
dt1 = new Date(date1);  
dt2 = new Date(date2);  
return Math.floor((Date.UTC(dt2.getFullYear(), dt2.getMonth(), dt2.getDate()) - Date.UTC(dt1.getFullYear(), dt1.getMonth(), dt1.getDate()) ) /(1000 * 60 * 60 * 24));  
}  
console.log(date_diff_indays('04/02/2014', '11/04/2014'));  
console.log(date_diff_indays('12/02/2014', '11/04/2014'));