selectDate

selects the specified date

void selectDate(string|Date date, [boolean mode,boolean multiple] );

date	string\|Date	a Date object or a string representing a date
mode	boolean	true - to show the selected date in the calendar, false - not to show the selected date
multiple	boolean	true - to select one more date (relevant for multiselect:true), false - to discard the previous selection

webix.ui({
    view:"calendar",
    id:"calendar1"
});
$$('calendar1').selectDate(new Date(2012,3,30));

Details

The method is analogous to setValue.