javascript - Validating date input field with onsubmit -

i looking everywhere, couldn't find code problem. have input fields, users using send online requests. , 1 of fields date field, somehow validate in way, allowed if entered date somewhere between today , 8 days before. example: if today 29 november , allowed enter date between 21st-29th november , nothing else , shown alert window when have entered wrong date pick days minicalendar part resolved, need validating. if post working code, grateful. thank you

use jquery ui datepicker, script below:

    $(function() {     var currentdate = new date();     var maxalloweddate = new date(currentdate);     maxalloweddate.setdate(currentdate.getdate() + 8);     $( "#datepicker" ).datepicker({          changeyear: true,         mindate: '0',         maxdate: '+7d',     });     $('#datepicker').change(function(){      var enteredval = new date(this.value);         if(enteredval.gettime() < currentdate.gettime() || enteredval.gettime() > maxalloweddate.gettime()) {             alert("invalid");         } else {             alert("valid");         }     }); }); 

and ui:

<div class="demo">  <p>date: <input type="text" id="datepicker"></p> 

here jsfiddle demo: http://jsfiddle.net/pjkz7k0t/1/