如何把这个判断条件里面的内容写成一个函数， 然后再这个判断里面调用

if (mul == "*"){
save = save.substr(0,save.length-calculate(firstCarry,secondCarry));
secondCarry = firstCarry * secondCarry;
save = save +secondCarry;
}
把 ：save = save.substr(0,save.length-calculate(firstCarry,secondCarry));
secondCarry = firstCarry * secondCarry;
save = save +secondCarry; 写一个函数
然后在if（mul=="*"）{ }里面调用

function saveContent(){
save = save.substr(0,save.length-calculate(firstCarry,secondCarry));
secondCarry = firstCarry * secondCarry;
save = save +secondCarry;
}
if（mul=="*"）{
saveContent();
}