public/javascript/libs/select2.js
function () {
            var placeholderOption;
            return this.opts.element.attr("placeholder") ||
                this.opts.element.attr("data-placeholder") || // jquery 1.4 compat
                this.opts.element.data("placeholder") ||
                this.opts.placeholder ||
                ((placeholderOption = this.getPlaceholderOption()) !== undefined ? placeholderOption.text() : undefined);
        }
function () {
            var placeholderOption;
            return this.opts.element.attr("placeholder") ||
                this.opts.element.attr("data-placeholder") || // jquery 1.4 compat
                this.opts.element.data("placeholder") ||
                this.opts.placeholder ||
                ((placeholderOption = this.getPlaceholderOption()) !== undefined ? placeholderOption.text() : undefined);
        }
abstract