function checkDigitSum(s) {// replace each letter by numerical equivalent to create new string newS
    var n    
    newS = ""
    for (var i = 0; i<s.length; ++i ) {
        var a = s.charCodeAt(i)    
        if (a>=65 & a<=90) {n = a - 55}
            else {n = s.charAt(i)}
        newS = newS + n }
    // check digit sum by long division, starting with first two digits
    var newM = parseInt(newS.substring(0,2),10)
    var r = newM % 97
    for (i = 2; i <newS.length; ++i) {
        newM = 10*r + parseInt(newS.substring(i, i+1),10)
        r = newM % 97}
    if (r==1) {document.imgCheck.src="checked.gif"; document.imgResult.src="resultOK.gif"}
    else {document.imgCheck.src="checked.gif"; document.imgResult.src="resultNo.gif"}        
}

Lparameters s

Local N, newS
newS = ""
For i=1 To Len(s) Step 1
   a=Asc(Substr(s,i,1))
   If a>=65 And a<=90
      N=a-55
   Else
      N=Val(Substr(s,i,1))
   Endif
   newS=newS+Alltrim(Str(N))
Next

Local newM, r
newM=Int(Val(Substr(newS,1,2)))
r=Mod(newM,97)

For i=3 To Len(newS) Step 1
   newM=10*r+Int(Val(Substr(newS,i,i+1)))
   r=Mod(newM,97)
Next

If r=1 && exactly
   ? "All OK"
Else
   ? "Something wrong in danish kingdom"
Endif