Below is the script that gives the first business day of the month in it
var date = new Date(), y = date.getFullYear(), m =date.getMonth();
var firstDay = new Date(y, m, 1);
var ilkis = "";
if(firstDay.getDay() == "6"){
ilkis = firstDay.getDate() + 2;
}
else if(firstDay.getDay() == "0"){
ilkis = firstDay.getDate() + 1;
}
else{
ilkis = firstDay.getDate();
}
if (ilkis<10) {
ilkis = '0' + ilkis;
}
var dayString = ilkis.toString();
var month = date.getMonth()+1;
if (month<10) {
month = '0' + month;
}
var monthString = month.toString();
var year = date.getUTCFullYear();
var yearString = year.toString();
var firstWorkDay=yearString+'-'+monthString+'-'+dayString+' 09:00:00';
execution.setVariable("firstWorkDay",firstWorkDay);