cfscript I'm trying to write Please help :)

Here's a cfscript along the lines of what you asked for. There's other ways to do it, of course, but I thought this approach would be helpful to you.

<cfscript>
/* takes a string as an argument and adds as many zeroes as it takes to make the string be exactly 6 characters. */
function PadWithZeroes()
{
var VarToTest = "";
var ValToReturn = "";
var VarLen = 0;
var DesiredVarLen = 6;

if (StructCount(Arguments) EQ 1)
    {
    /* Use Trim(Arguments[1]) only if you do NOT want to add zeroes to one or more empty spaces */
    VarToTest = Trim(Arguments[1]);
    VarLen = Len(VarToTest);
    TimesToLoop = DesiredVarLen - VarLen;
    }

if (TimesToLoop GT 0)
    {
    for (q = 1; q LTE TimesToLoop; q = q + 1)
        {
        VarToTest = "0" & VarToTest;
        }
    ValToReturn = VarToTest;
    return ValToReturn;
    }
else
    {
    return false;
    }
}

// the rest is for testing/viewing the function etc.

NumberToUse = 4;
if (IsDefined("URL.NumberToUse") AND Len(Trim(URL.NumberToUse)) LTE 6)
    {
    NumberToUse = Trim(URL.NumberToUse);
    }

</cfscript>

<cfoutput>

<br>

NumberToUse=#NumberToUse#

<br>
<br>
PadWithZeroes(NumberToUse) = #PadWithZeroes(NumberToUse)#
<br>
<br>

</cfoutput>