Quick and easy one!

Hello!
Just a quick question:
I have three dynamic text boxes with numbers in them and I want to get the total of these numbers. This is the code I’ve got:

var final_total = 0;
final_total = total1_complete+total2+total3;

total1_complete being the first box and so on . . .

But this doesn’t give me the total is just adds the three numbers after each other! Where have I gone wrong ? ? ?
Many thanks