JavaScript Date Object Setmonth method bug

In fact, there is no bug, but the JS date object to overflow time for their own processing.

First set your system time to January 31, 2013, this step is important, otherwise it may not occur, and then execute the following code

The code is as follows	Copy Code
var t = new Date (); T.getmonth (); Output 0, now gets the correct value because the getmonth is indexed from 0 T.setmonth (3); Set Month to April T.getmonth (); Output 4, where this should output 3 of the var t = new Date (); T.getmonth (); Output 0, now gets the correct value because the getmonth is indexed from 0 T.setmonth (3); Set Month to April T.getmonth (); Output 4,

Here should be output 3 you will find that you clearly set the month value of 3, but getmonth time output 4. At this point, you may be more puzzled. Let's take a look at the time now.

The code is as follows	Copy Code
Console.log (t); Wed May 2013 11:47:31 gmt+0800 (CST) console.log (t); Wed May 2013 11:47:31 gmt+0800 (CST) setmonth (3)

Specify the set date to April, but April is only 30 days, this time is 2013-04-31, but April is not 31 days. So JS processed the overflow date and automatically set the month to May 1

For this problem is also very good to solve, as long as the date before the Setmonth set to the monthly date, 1-28 can be.

code is as follows	copy code
var t = New Date (); T.setdate (1); T.setmonth (3); T.getmonth ();//Output 3