Get the first day of the next month and the day of the week in javascript_time and date

If today is May On the 30th, through the above code, I should get the next month, that is, what day of the week is June 1st? And assign it to the variable fday;
Sure enough, I can get it correctly;
The process is:
1. Execute this odatef.setFullYear(2012); Then the odatef object will be: May 30, 2012 Day;
2. Execute to this sentence odatef.setMonth(5); Then the odatef object will be: June 30, 2012;
3. Execute to this sentence odatef.setDate(1); Then odatef The object will be: June 1, 2012;
4. Execute this sentence ordatef.getDay(); Then what we get is: June 1, 2012, what day of the week it is, exactly what we want !


If today is May 31st, using the same code above, I cannot correctly get the day of the week next month.
Reason:
1. Execute this odatef.setFullYear(2012); Then the odatef object will be: May 31, 2012;
2. Execute this odatef.setMonth(5); Then the odatef object will be: June 31, 2012; the problem lies in the second step: June does not have a 31st, so it will jump to July. Then the odatef object will be: July 2012 On the 31st, if there is no 31st in July, continue to jump to August until there is a month with the 31st;
3. Execute this sentence odatef.setDate(1); Then the odatef object will be: July 2012 Month 1;
4. Execute this sentence ordatef.getDay(); Then what we get is: July 1, 2012, what day of the week it is, which is not what we want! ~
Solution: Change the position of the statement and set the date first, then the month!

1. Execute this sentence odatef.setFullYear(2012); Then the odatef object will be: May 31, 2012; 2. Execute this sentence odatef.setDate(1); Then the odatef object will be: May 1, 2012;
3. Execute this sentence odatef.setMonth(5); Then the odatef object will be: June 1, 2012;
4. Execute this sentence ordatef.getDay(); Then what you get is: 2012 June 1st, what day of the week is it! ~~~
Summary: It is necessary to understand each statement, what is the result of execution, or what is returned. I always thought that it was just to set the year and month. No consideration is given to the results or what is returned after setting!