Parsing an email Regular Expression

In the past, the regular expression was used to open the syntax document of the regular expression, and then re-reference and compare it one by one. Once it is used, it will be left behind, so I forget it every time I use it, every time I come back, no wonder the regular expression is like "tianshu ".
While I am using the email regular expression, my understanding of the Regular Expression of email can be recorded as a case! My email regular is from regexbuddy's library, as follows:
\ B [A-Z0-9. _ %-] + @ [A-Z0-9. _ %-] + \. [A-Z] {2, 4} \ B
You can open the regular expression syntax document (that is, the regular expression chapter in the Javascript Manual)
In comparison, the regular expressions mainly include:
\ B Indicates matching a word boundary
[A-Z0-9. _ %-] indicates characters that can match A-Z 0-9. _ %-
+ Indicates a character that can match 1-N A-Z 0-9. _ %-
@ Special characters of the email
[A-Z0-9. _ %-] is similar
\. Indicates matching. Because. is a special character in a regular expression, it must be escaped \.
[A-Z] {2, 4} indicates 2 to 4 characters configuring a-z
\. [A-Z] {2, 4} \ B the entire view is that the last word must be 2-4 characters, with a vertices in front.
Last
Several Regular Expression debugging tools are recommended.
Http://www.cnblogs.com/Heroman/archive/2005/01/13/91265.html