var a=0;
var b=3;
function com(){
a=1;
return function(){
b=a+a;
}
}
com();
console.log(a); //1
console.log(b); //3
------------------------------
var a=0;
var b=0;
function com(){
a=1;
c=5;
return function(c){
b=a+c;
}
}
com()();
console.log(a); //1
console.log(b); //NaN
console.log(c); //5