Straight from the link...
Who knows... but what browser do you use? It maybe something other than the code editor.
Code:
'**************************************************************** 
'*  Name    : Number Input routine                             *
'*  Author  : Charles Linquist                                  *
'*  Notice  : Copyright (c) 2011 Charles Linquist               *
'*          : All Rights Reserved                               *
'*  Date    : 9/13/2011                                         *
'*  Version : 1.0                                               *
'*  Notes   : For the forum                                     *
'*          :                                                   *
'****************************************************************

        DEFINE OSC 40                                                           
        DEFINE NO_CLRWDT 1
        DEFINE _18F8723 1
        DEFINE HSER_RCSTA 90H
        DEFINE HSER_TXSTA 20H                                                   
        DEFINE HSER_CLROERR 1
        define HSER_BAUD 9600

       

        Keyin var byte
        Maxnum var byte
        YY var word
        POSN var byte
        IsNeg var bit
        AllowNeg var bit
        TimedOut var bit
        InputString var byte [10]
        Result Var word
        XN var byte

        BS CON 8
        ESC cON 27
        LF con 10
        SP con 32
        CR con 13

        TRISC = %10111111  ; Just for the serial port
topp:        
       allowneg = 1
        
  hserout [CR,Lf,"Input a number "]
   gosub getnum
   hserout [CR,LF,"You entered "]
   
   IF isneg = 1 then 
      Hserout [SDEC Result,CR,LF]
    ELSE
      hserout [dec Result,CR,LF]
    ENDIF  
   
   Goto topp        
        

GetNum:
        Result = 0
        MaxNum = 5     ; set for max number of digits you will accept
        YY = 1
        POSN=0
        IsNeg = 0
        TimedOut = 0
        ArrayWrite InputString,[Rep $FF\8]  ; Fill with $FF
 
GetMoreN:              
        HSERIN 9000,InputTimeout,[Keyin]
            IF Keyin = ESC THEN ZeroNum
            If Keyin = CR THEN DunInputn
            If allowNeg then
            IF Keyin = "-" and Posn = 0 THEN 
                IsNeg = 1
                Hserout ["-"]
                goto GetMoreN
            ENDIF 
            endif   
            IF Keyin = BS THEN
               HSEROUT [BS,SP,BS]
               IF POSN > 0 THEN
                  POSN = POSN - 1
                  InputString [POSN] = $FF
                  GOTO GetMoreN
               ENDIF   
            ENDIF
        IF Keyin < "0" or Keyin > "9" THEN GetMoreN 
        HSEROUT [Keyin]
        InputString [POSN] = Keyin - "0"
        IF POSN >= (MaxNum -1) THEN DunInputN
        POSN = POSN +1
        GOTO GetMoreN
DunInputN:

       More code here