doCallback = function( success )
			{
				if ( callback )
				{
					if ( isString )
						callback.call( scope, success );
					else
						callback.call( scope, completed, failed );
				}
			}
Loads one or more external script checking if not already loaded
previously by this function.
@param {String|Array} scriptUrl One or more URLs pointing to the
		scripts to be loaded.
@param {Function} [callback] A function to be called when the script
		is loaded and executed. If a string is passed to "scriptUrl", a
		boolean parameter is passed to the callback, indicating the
		success of the load. If an array is passed instead, two array
		parameters are passed to the callback; the first contains the
		URLs that have been properly loaded, and the second the failed
		ones.
@param {Object} [scope] The scope ("this" reference) to be used for
		the callback call. Default to {@link CKEDITOR}.
@param {Boolean} [noCheck] Indicates that the script must be loaded
		anyway, not checking if it has already loaded.
@example
CKEDITOR.scriptLoader.load( '/myscript.js' );
@example
CKEDITOR.scriptLoader.load( '/myscript.js', function( success )
    {
        // Alerts "true" if the script has been properly loaded.
        // HTTP error 404 should return "false".
        alert( success );
    });
@example
CKEDITOR.scriptLoader.load( [ '/myscript1.js', '/myscript2.js' ], function( completed, failed )
    {
        alert( 'Number of scripts loaded: ' + completed.length );
        alert( 'Number of failures: ' + failed.length );
    });