Warning...javascripty answer.

To enforce a "White List" of allowable characters, I do the following:

1. Add a class to the input on which I'd like the validation to be active, regularExpressionCheck
2. Add an additional property to the input, regularExpressionMatch
   1. The value of the property in my case it set to an application item, regularExpressionMatch="&ALLOWABLE_DATASET_REG_EXP." but, you couold hard code one here. For me, this item, ALLOWABLE_DATASET_REG_EXP, is set to [^A-Za-z0-9_], i.e. just letters, numbers and _.
3. Then I have a bit a JS to check if the value matches the RegExp whitelist.

function regularExpressionCheck( validationValue, validationDisplay, regularExpressionMatch )
{
    var testRegExpObj = new RegExp( regularExpressionMatch );


    var hasUndesiredContent = testRegExpObj.test( validationValue );


    if( hasUndesiredContent === true )
    {
        var invalidCharacters = '';
        var currentForbiddenCharacter;


        while ( (invalidCharacterArray = testRegExpObj.exec( validationValue ) ) !== null )
        {
            currentForbiddenCharacter = invalidCharacterArray[0];


            if( invalidCharacters.indexOf(currentForbiddenCharacter) === -1 )
            {
                invalidCharacters = invalidCharacters + currentForbiddenCharacter;
            }


            validationValue = validationValue.substr( testRegExpObj.lastIndex + 1 );
        }
        
        this.errorMsg = validationDisplay + ' contains disallowed characters: "' + invalidCharacters + '"';
        this.cellHasError = true;      
    }
    else
    {
        this.cellHasError = false;
    } 
}

So, to call this, I just find any elements with this class, whenever one if found, I call:

regularExpressionMatch = $(childNode).attr("regularexpressionmatch");
validationCheckObj = new regularExpressionCheck( childValue, displayHeader, regularExpressionMatch );  

If the validation object has an error, raise it.

if ( validationCheckObj.cellHasError === true )
{                                          
    conditionallyAddError( validationCheckObj.cellHasError,
                           $(childNode),
                           $(childNode).attr('id'),
                           validationCheckObj.errorMsg,
                           errorList, 
                           internalErrorCnt,
                           errorClass );    
                           
    errorCnt = errorCnt + 1;                                                                                                                                                                   
}