Calculating Total score in appraisal

i am calculating Supervisor Score + achievement_rating to fine Total score: i used below code but not working.

cur_frm.cscript.calculate_final_total = function(doc,cdt,cdn){
var total = 0;
total = (supervisor_score + achievement_rating);
doc.final_rating = flt(total);
refresh_field(‘final_rating’);

}

please help me

by using below code i can add " supervisor score" + “achievement rating”, but when i change “supervisor score” later, its not adding, only after i change “final rating” only it add that change value

cur_frm.cscript.calculate_total2 = function(doc,cdt,cdn){
	//var vel = doc.goals || [];
	var vil = doc.competancies || [];
	var total2 = 0;
	for (var i = 0; i<vil.length; i++){
		total2 = flt(total2)+flt(vil[i].score_supervisors);
	}
	doc.achievement_rating = flt(total2);
	refresh_field('achievement_rating');
	
	//calculate Final score(competancies+achievement)
	doc.final_rating = flt(doc.achievement_rating) + flt(doc.total_supervisor);
	refresh_field('final_rating');

}