Javascript example

HTML

<input type="submit" id="byBtn" value="Click me" onclick="foo()"/>

JavaScript

function foo()
{
   var barra = "74893.12004 21627.007186 37931.981056 7 60750000001400";
   var vencimento = 1001;
   var date = new Date('10/07/1997');
   date.setTime(date.getTime() + (vencimento * 24 * 60 * 60 * 1000));
    
   alert(("0" + (date.getDate())).slice(-2) + '/' + ("0" + (date.getMonth() + 1)).slice(-2) + '/' + date.getFullYear());
}