addMarkedTimespan works with days as number but not date

why would the using a date not work?

when I use a number like below the day is blocked correctly? (5 for Friday)

-D

scheduler.addMarkedTimespan({
//days: 5, // marks each Friday WORKS

days: new Date(2014,5,30),                       // NOT WORKING

//start_date: new Date(2014,5,20),            // NOT WORKING
//end_date:   new Date(2014,6,1),                 // NOT WORKING

//zones: "fullday",       // marks the entire day 
zones:[10*60,11*60],                              
css:   "gray_section",   // the applied css style 
type: "dhx_time_block",                           

});
scheduler.updateView();

solved it

month may is number 4

-D

Yep, in javascript month numbers starts from 0 ( 0 - January )