Javascript html date control (validation)

Here is a sample code for an html input date control include DATE validation!
I searched a lot for such method for integration with PHP page but was little difficult.

Here is the HTML CODE:

<input id="inputDate1" name="Field1" value="21/07/2006" type="text" onblur="validateDate(this, '/')" maxlength="10">

<button onclick="setTodayDate(this.previousSibling, '/')">today</button>

Here is the JAVASCRIPT CODE:

function validateDate(p_inputObj, delim)
{
var text = p_inputObj.value;
var errorMsgs = "Following error(s) :\n";
var isDateCorrect = true;

var delim1 = text.indexOf(delim);
var delim2 = text.indexOf(delim, delim1+1);
if (delim2 <= delim1)
{
isDateCorrect = false;
errorMsgs = errorMsgs + "- Must be in format of dd/mm/yyyy like (21/09/2008)\n";
}
else
{
var day = parseInt(text.substring(0, delim1), 10);
var splitter1 = text.substring(delim1, delim1+1);
var month = parseInt(text.substring(delim1+1, delim2), 10);
var splitter2 = text.substring(delim2, delim2+1);
var year = parseInt(text.substring(delim2+1), 10);

if (isNaN(day) || isNaN(month) || isNaN(year))
{
isDateCorrect = false;
if (isNaN(day)) { errorMsgs = errorMsgs + "- Day not in correct format!\n"; }
if (isNaN(month)) { errorMsgs = errorMsgs + "- Month not in correct format!\n"; }
if (isNaN(year)) { errorMsgs = errorMsgs + "- Year not in correct format!\n"; }
}
else
{
if (day<1)
{
errorMsgs = errorMsgs + "- Day must be between grater than 0\n";
isDateCorrect = false;
}

if (month>12 || month<1)
{
isDateCorrect = false;
errorMsgs = errorMsgs + "- Month must be between 01 to 12\n";
}
else
{
if (month==1 || month==3 || month==5 || month==7 || month==8 || month==10 || month==12 )
{
if (day>31)
{
errorMsgs = errorMsgs + "- Day must be between 1 to 31\n";
isDateCorrect = false;
}
}
else if(month==2)
{
// is leap year
if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0))
{
if (day>29)
{
errorMsgs = errorMsgs + "- Day must be between 1 to 29\n";
isDateCorrect = false;
}
}
else
{
if (day>28)
{
errorMsgs = errorMsgs + "- Day must be between 1 to 28\n";
isDateCorrect = false;
}
}
}
else
{
if (day>30)
{
errorMsgs = errorMsgs + "- Day must be between 1 to 30\n";
isDateCorrect = false;
}
}
}

if (year<2000)
{
isDateCorrect = false;
errorMsgs = errorMsgs + "- Year not valid. must be more than 2000!\n";
}
else if (year>9999)
{
isDateCorrect = false;
errorMsgs = errorMsgs + "- Year must be 4 digits!\n";
}
}
}

if (isDateCorrect == true)
{
var newStr = (day<10 ? '0' : '') + day + delim +
(month<10 ? '0' : '') + month + delim +
year; // +" "+hour+":"+minute+" "+AMPM;
p_inputObj.title = '';
var date = new Date();
date.setFullYear(year, month-1, day);
p_inputObj.dateVal = date;
p_inputObj.value = newStr;
p_inputObj.style.backgroundColor='#FFFFFF';
return true;
}
else
{
//alert(errorMsgs);
errorMsgs = errorMsgs.substring(0, errorMsgs.length-1);
p_inputObj.dateVal = null;
p_inputObj.title = errorMsgs;
p_inputObj.style.backgroundColor='#ffaaaa';
p_inputObj.focus();
return false;
}
}

function setTodayDate(p_inputObj, p_delim)
{
var dtNow = new Date();
var day = dtNow.getDate();
var month = dtNow.getMonth() + 1;
var year = dtNow.getFullYear();
p_inputObj.value = (day<10 ? '0' : '') + day + p_delim +
(month<10 ? '0' : '') + month + p_delim +
year;
}

Date format if dd/MM/yyyy but it can also be MM/dd/yy or yyyy!
Enjoy... :)