I used the date.toUTCString function but the returned result is always one month later than the time I need.
For examle, I used " var date:Date=new Date();
The UTC month value of the date is 7, so the month value in str is supposed to be "July". But I got the value "Aug" in str instead...
So what happended here? Does this related to my system time or browser?
Yep. It's a somewhat inintuitive design decision since it's the only date field that is 0-indexed. My guess is that there is an enumeration of the month names behind the scenes. However, you should learn always check the Language Reference first. Keep it open while developing and you can save yourself some frustration as there is a lot that you can quickly learn about a class once you get used to the layout of the documentation.