why is undefined written here

Question

var a="w3resource";
for(var i=a.length;i>=0;i--){
document.write(a[i]);
}
why is it printing undefined along with the word?

Answer 1

Hi Ali Zain
Try this
var a="w3resource";
for(var i=a.length-1;i>-1;--i){
document.write(a[i]);
}

Answer 2

The last index of a is not a.length, but a.length-1. a[i] doesn't exist thus undefined.

Answer 3

var a="w3resource";
for(var i=a.length-1;i>=0;i--){
document.write(a[i]);
} // I am just added a.length -1.
1.Now try this above code.
2. a.length is 10 but array index starts from 0 to 9.
3.first a[10] is going to print undefined.That's all.

Answer 4

Because we can't run this here ..
Give the code please so we can run it

Answer 5

Got it! Thanks alot