javascript substring
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.
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));
You have three options in Javascript:
//slice
//syntax: string.slice(start [, stop])
"Good news, everyone!".slice(5,9); // extracts 'news'
//substring
//syntax: string.substring(start [, stop])
"Good news, everyone!".substring(5,9); // extracts 'news'
//substr
//syntax: string.substr(start [, length])
"Good news, everyone!".substr(5,4); // extracts 'news'