Here is a utils function that I've used for years.
function getCompanyDate(){
var currentDateTime = new Date();
var companyTimeZone = nlapiLoadConfiguration('companyinformation').getFieldText('timezone');
var timeZoneOffSet = (companyTimeZone.indexOf('(GMT)') == 0) ? 0 : new Number(companyTimeZone.substr(4, 6).replace(/\+|:00/gi, '').replace(/:30/gi, '.5'));
var UTC = currentDateTime.getTime() + (currentDateTime.getTimezoneOffset() * 60000);
var companyDateTime = UTC + (timeZoneOffSet * 60 * 60 * 1000);
return new Date(companyDateTime);
}
It uses your company's NetSuite settings and timezone. This will return the date in the correct timezone assuming your NetSuite settings are correct.
You could then essentially do:
function currentDate(addDays) {
if (addDays == null||addDays == undefined) {
addDays = 0;
}
var currentdate = getCompanyDate();
var current = nlapiAddDays(currentdate,addDays);
var day = current.getDate();
var month = current.getMonth()+1
var year = current.getFullYear();
return day+'/'+month+'/'+year;
}