javascript substring

Question

the most darndest thing! the following code prints out 'llo' instead of the expected 'wo'. i get such surprising results for a few other numbers. what am i missing here?

alert('helloworld'.substring(5, 2));

Answer 1

Check the substring syntax:

substring(from, to)

from Required. The index where to start the extraction. First character is at index 0

to Optional. The index where to stop the extraction. If omitted, it extracts the rest of the string

I'll grant you it's a bit odd. Didn't know that myself.

What you want to do is

alert('helloworld'.substring(5, 7));

Answer 2

alert('helloworld'.substring(5, 2));

The code above is wrong because the first value is the start point to the end point.E.g move from char 5 which is o and go to char 2 which is the l so will get llo So you have told it to go backwards.

What yuou want is

alert('helloworld'.substring(5, 7));

Answer 3

You're confusing substring() and substr(): substring() expects two indices and not offset and length. In your case, the indices are 5 and 2, ie characters 2..4 will be returned as the higher index is excluded.

Answer 4

I know this has likely been put to rest but im confussed. If the first character 'h' is 0 in then surely the from value 5 will be 'w'