Looking on the internet deeply has found these results:

both the boys is the most popular phrase on the web.

both of the boys 135,900 results on the web	both the boys 129,400,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Both of the boys got injured, but they ran for the river. As they swum downstream with the current, the men ran up to the bank and started shooting at them, ... You can also say 'Both the boys were Hungarian' or 'Both of the boys were Hungarian'. There is no difference in meaning. Be Careful! Don't say 'Both of boys ... May 31, 2013 ... The correct answer was apparently the place of the apostrophe: in terms of the above example, it should read "both of the boys' parents" ... There are times when it is important to use “each” instead of “both.” Few people will be confused if you say “I gave both of the boys a baseball glove,” meaning “I ...	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

both of the boys

135,900 results on the web

both the boys

129,400,000 results on the web

More popular!

Both of the boys got injured, but they ran for the river. As they swum downstream with the current, the men ran up to the bank and started shooting at them, ...
You can also say 'Both the boys were Hungarian' or 'Both of the boys were Hungarian'. There is no difference in meaning. Be Careful! Don't say 'Both of boys ...
May 31, 2013 ... The correct answer was apparently the place of the apostrophe: in terms of the above example, it should read "both of the boys' parents" ...
There are times when it is important to use “each” instead of “both.” Few people will be confused if you say “I gave both of the boys a baseball glove,” meaning “I ...

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.