JS Regular expression Matching mailbox

For example, ' zo+ ' can match "Zo" and "Zoo", but cannot match "Z". + is equivalent to {1,}. {n,m} m and n are non-negative integers, where n <= m. Matches n times at least and matches up to M times. For example, "o{1,3}" will match the first three o in "Fooooood". ' o{0,1} ' is equivalent to ' o '. Notice that there is no space between the comma and the two number.

Javascript Mailbox Validation Regular Expression example

The code is as follows	Copy Code
Myreg =/^ ([a-za-z0-9]+[_|_|.]?) *[a-za-z0-9]+@ ([a-za-z0-9]+[_|_|.]?) *[a-za-z0-9]+. [A-za-z] {2,4}$/; Javascript

Example of a mailbox validation regular expression

code is as follows	copy code
< Script type= "Text/javascript" Function Isemail (val) {            var myreg =/^ ([a-za-z0-9]+[_|_|.]?) *[a-za-z0-9]+@ ([a-za-z0-9]+[_|_|.]?) *[a-za-z0-9]+. [A-za-z] {2,4}$/;             if (!myreg.test (val))            return ' is not a mailbox ';           return ' is mailbox '; }; Alert (isemail (' i@fufuok.com ')); </script>

Two. Explain the relevant meaning
     1. /^$/This is a generic format.
         ^ matches the start position of the input string; $ matches the end position of the input string
     2. Inside, enter the functionality you want to implement.
        * matches the preceding subexpression 0 or more times;
       + Matches the preceding subexpression one or more times;
       Matches the preceding subexpression 0 times or once;
       d  matches a numeric character, equivalent to [0-9]