How do I check for null date entires using custom JScript on a SharePoint NewForm.aspx?

Question

Hi,
I have the below JScript:
/*Function to convert the US Date format to UK date format */
function parseDate(input) {
var parts = input.split('/');
// new Date(year, month [, date [, hours[, minutes[, seconds[, ms]]]]])
return new Date(parts[2], parts[1]-1, parts[0]); // months are 0-based
/*Function to check if end date is before the start date */
function checkDates(){
var sd = parseDate($("input[title='From']").val());
var ed = parseDate($("input[title='Until']").val());
if(sd > ed) {
alert("Please check From and Until Date");
$("input[value$='Save']").attr('disabled', true); //hide save button
else
$("input[value$='Save']").attr('disabled', false); //show save button
The above works fine for checking sd > ed but I can't seem to check for null's, I have attempted the below which doesn't work:
/*Function to convert the US Date format to UK date format */
function parseDate(input) {
var parts = input.split('/');
// new Date(year, month [, date [, hours[, minutes[, seconds[, ms]]]]])
return new Date(parts[2], parts[1]-1, parts[0]); // months are 0-based
/*Function to check if end date is before the start date */
function checkDates(){
var sd = parseDate($("input[title='From']").val());
var ed = parseDate($("input[title='Until']").val());
if( (sd > ed) || (sd == null) || (ed == Null) ) {
alert("Please check From and Until Date");
$("input[value$='Save']").attr('disabled', true); //hide save button
else
$("input[value$='Save']").attr('disabled', false); //show save button
Any help appreciated.

Answer 1

Hi aspnet-scotland,
Please post ASP.NET related questions in
ASP.NET forums where you could receive better responses.
Thanks for your understanding.
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
Click
HERE to participate the survey.