public/javascripts/yui/carousel/carousel-debug.js
function (val) {
            var carousel = this, numItems = carousel.get("numItems");

            if (JS.isNumber(val)) {
                if (numItems === 0 && val == numItems) {
                    return true;
                } else {
                    return (val >= 0 && val < numItems);
                }
            }

            return false;
        }
function (val) {
            var carousel = this, numItems = carousel.get("numItems");

            if (JS.isNumber(val)) {
                if (numItems === 0 && val == numItems) {
                    return true;
                } else {
                    return (val >= 0 && val < numItems);
                }
            }

            return false;
        }
function ( val ) { var carousel = this , numItems = carousel . get ( "numItems" ) ; if ( JS . isNumber ( val ) ) { if ( numItems === 0 && val == numItems ) { return true ; } else { return ( val >= 0 && val < numItems ) ; } } return false ; }
Validate the firstVisible value.

@method _validateFirstVisible
@param val {Number} The first visible value
@return {Boolean} The status of the validation
@protected
Validate the firstVisible value .