Get today date in google appScript

Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")

You can change the format by doing swapping the values.

• dd = day(31)
• MM = Month(12) - Case sensitive
• yyyy = Year(2017)

function changeDate() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(GA_CONFIG);
    // You could use now Date(); on its own but it will not look nice.
    var date = Utilities.formatDate(new Date(), "GMT+1", "dd/MM/yyyy")
    var endDate = date
}

The Date object is used to work with dates and times.

Date objects are created with new Date()

var now = new Date();

now - Current date and time object.

function changeDate() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(GA_CONFIG);
    var date = new Date();
    sheet.getRange(5, 2).setValue(date); 
}

Google Apps Script is JavaScript, the date object is initiated with new Date() and all JavaScript methods apply, see doc here