/*
substr() returns a part of a string. substr(2,6) return from the second character (start at 0) and 6 long.
substring() returns a part of a string. substring(2,6) returns all characters from the second character (start at 0) and up to, but not including, the sixth character.
*/
var str="JavaScript is great!"
document.write(str.substr(2,6))
document.write("
")
document.write(str.substring(2,6))