CFLib.org – Common Function Library Project

Description:
Returns a boolean result (true or false) of whether the provided number passes the ABA check-digit algorithim. ABA ( numbers must be exactly 9 digits long. They are used to uniquely identify a bank for wire transfers and ACH (Automated Clearing House).

Return Values:
Returns a Boolean.

Example:

<cfset abaNo = 123456780>
<cfset abaNo2 = 123456789>

<cfoutput>
#abaNo# is#iif(isAba(abaNo),DE(''), DE(' not'))# a valid ABA Routing Number.<br>
    #abaNo2# is#iif(isAba(abaNo2),DE(''), DE(' not'))# a valid ABA Routing Number.<br>
</cfoutput>

Parameters:

Full UDF Source:

/**
 * Checks that a number is a valid ABA routing number.
 * 
 * @param number      Number you want to validate as an ABA routing number. 
 * @return Returns a Boolean. 
 * @author Michael Osterman (mosterman@highspeed.com) 
 * @version 1, March 21, 2002 
 */
function isABA(number) {
    var j = 0;
    var cd = 0; //check-digit value
    var result = false;
    var modVal = 0; //compared to check-digit
    var weights = ArrayNew(1);
    
    ArraySet(weights, 1, 8, 0);
    
    //set the weights for the following loop
    weights[1] = 3;
    weights[2] = 7;
    weights[3] = 1;
    weights[4] = 3;
    weights[5] = 7;
    weights[6] = 1;
    weights[7] = 3;
    weights[8] = 7;
    
    cd = Right(number,1);
    
    for (i = 1; i lte 8; i=i+1) 
    {
        j = j + ((Mid(number,i,1))*weights[i]);
    }
    
    modVal = ((10 - (j mod 10)) mod 10);
    
    if (modVal eq cd)
    {
        result = true;
    }
    
    return result;
}