I've tried to create a fare calculator, but when i click on the button nothing happens, i haven't used action script for a while and cant work out why its not working.

Any help appreciated.

Code:
//----------- NUMBERS ------------\\
on(release){
	var str_mileage:String
	var str_pricepm:Number
	var str_firstmile:Number
	var str_fare:Number
	
//----------- CALCULATE ------------\\
		str_mileage = miles_txt.text;
	str_pricepm = 1.50;
	str_firstmile = 1.70;
	
	str_fare = parseInt(str_mileage) * str_pricepm + str_firstmile
	str_fare.toString();
	fare_txt.text = String(str_fare)
	}