Question

for (var i=0;i<5;++i){
alert(i);

}


for (var i=0;i<5;i++){
alert(i);

}

These two constructs return the same result: 0,1,2,3,4. Why? What are the differences between them? Does it matter what increment i use in for loop?

Answer 1

If you put ++ in front of the variable you increment the value before returning it (in that statement), if you put it behind you return the value, then increment it afterwards. Since you are doing nothing with the value in the statement the result after said statement is the same.

Consider this:

var i = 0;
var a = ++i; // a is 1
var b = i++; // b is also 1, i is now 2.