function Mid(str, start, len)
 /***
 IN: str - the string we are LEFTing
 start - our string's starting position (0 based!!)
 len - how many characters from start we want to get
 RETVAL: The substring from start to start+len
 ***/
 {
 // Make sure start and len are within proper bounds
 if (start < 0 || len < 0) return "";
 var iEnd, iLen = String(str).length;
 if (start + len > iLen)
 iEnd = iLen;
 else
 iEnd = start + len;
 return String(str).substring(start,iEnd);
 }
// Keep in mind that strings in JavaScript are zero-based, so if you ask
// for Mid("Hello",1,1), you will get "e", not "H". To get "H", you would
// simply type in Mid("Hello",0,1)
// You can alter the above function so that the string is one-based. Just
// check to make sure start is not <= 0, alter the iEnd = start + len to
// iEnd = (start - 1) + len, and in your final return statement, just
// return ...substring(start-1,iEnd)

.