Date Tme

try this:

document.getElementById('enddateTextBox').value = new Date((new Date(mYear, mMonth+1,1))-1).getDate ();

this is showing start date in both the textboxes not showing enddate in second textbox

this is how you can get date on the client side in javascirpt and assign to textbox:

mDate = new Date();
var mMonth = mDate.getMonth()+1;
var mDay = mDate.getDate();
var mYear = mDate.getFullYear();

document.getElementById('startdateTextBox').value = mMonth + '/' + mDay + '/' + mYear + ': ';
document.getElementById('enddateTextBox').value = mMonth + '/' + mDay + '/' + mYear + ': ';

Also do not forget to assign current date to the calendar control so to be consistent.