Here's a script that should meet your needs, storing the dateRange string of the form yyyy/mm/ddT00:00:00-yyyy/mm/ddT23:59:59
var currDate = new Date();
var date = currDate.getDate();
var month = currDate.getMonth() + 1; //turns out months are 0 indexed
var year = currDate.getFullYear();
if(month == 12 && date == 31) {
dateRange = "" + year + "/12/30T00:00:00-" + (year+1) + "/1/1T23:59:59";
}
else if(month == 1 && date == 1){
dateRange = "" + (year-1) + "/12/31T00:00:00-" + (year) + "/1/1T23:59:59";
}
else if(day == 31) {
dateRange = "" + year + "/" + month + "/" + (date-1) + "T00:00:00-" + year + "/" + (month+1) + "/1T23:59:59";
}
else if(day == 30 && (month == 4 || month == 6 || month == 9 || month == 11)) {
dateRange = "" + year + "/" + month + "/" + (date-1) + "T00:00:00-" + year + "/" + (month+1) + "/1T23:59:59";
}
else if(month == 2 && day == 28) {
if(year % 4 == 0 && year % 100 != 0) {
dateRange = "" + year + "/" + month + "/" + (date-1) + "T00:00:00-" + year + "/" + (month) + "/29T23:59:59";
}
else {
dateRange = "" + year + "/" + month + "/" + (date-1) + "T00:00:00-" + year + "/" + (month+1) + "/1T23:59:59";
}
}
else if(day == 1) {
if(month == 2 || month == 4 || month == 6 || month == 9 || month == 11) {
dateRange = "" + year + "/" + (month-1) + "/31T00:00:00-" + year + "/" + (month) + "/2T23:59:59";
}
else if(month == 3) {
if(year % 4 == 0 && year % 100 != 0) {
dateRange = "" + year + "/2/29T00:00:00-" + year + "/" + (month) + "/2T23:59:59";
}
else {
dateRange = "" + year + "/2/28T00:00:00-" + year + "/" + (month) + "/2T23:59:59";
}
}
else {
dateRange = "" + year + "/" + (month-1) + "/30T00:00:00-" + year + "/" + (month) + "/2T23:59:59";
}
}
else {
dateRange = "" + year + "/" + month + "/" + (date-1) + "T00:00:00-" + year + "/" + month + "/" + (date+1) + "T23:59:59";
}