src/openseadragon.js
function( element, className ) {
            element = $.getElement( element );

            if (!element.className) {
                element.className = className;
            } else if ( ( ' ' + element.className + ' ' ).
                indexOf( ' ' + className + ' ' ) === -1 ) {
                element.className += ' ' + className;
            }
        }
function( element, className ) {
            element = $.getElement( element );

            if (!element.className) {
                element.className = className;
            } else if ( ( ' ' + element.className + ' ' ).
                indexOf( ' ' + className + ' ' ) === -1 ) {
                element.className += ' ' + className;
            }
        }
function ( element , className ) { element = $ . getElement ( element ) ; if ( ! element . className ) { element . className = className ; } else if ( ( ' ' + element . className + ' ' ) . indexOf ( ' ' + className + ' ' ) === - 1 ) { element . className += ' ' + className ; } }
Add the specified CSS class to the element if not present.
@function
@param {Element|String} element
@param {String} className
Add the specified CSS class to the element if not present .