jui\DatePicker $dateFormat

The format string to be used for formatting the date value. This option will be used to populate the clientOption dateFormat. The value can be one of "short", "medium", "long", or "full", which represents a preset format of different lengths.

It can also be a custom format as specified in the ICU manual. Alternatively this can be a string prefixed with php: representing a format that can be recognized by the PHP date()-function.

For example:

'MM/dd/yyyy' // date in ICU format
'php:m/d/Y' // the same date in PHP format

If not set the default value will be taken from Yii::$app->formatter->dateFormat.