判断Email地址是否正确的几个函数(asp/php/javascript)

function is_email( str ){
p = /^([\w\.-]+)@([a-zA-Z0-9-]+)(\.[a-zA-Z\.]+)$/;
if(str.search(p) == -1){
return false;
}else{
return true;
}
}

function is_email($email){
$pattern="/^([\w\.-]+)@([a-zA-Z0-9-]+)(\.[a-zA-Z\.]+)$/i";//包含字母、数字、下划线_和点.的名字的email
if(preg_match($pattern,$email,$matches)){
return true;
}else{
return false;
}
}

function IsValidEmail(email)
dim names, name, i, c
IsValidEmail = true
names = Split(email, "@")
if UBound(names) <> 1 then
IsValidEmail = false
exit function
end if
for each name in names
if Len(name) <= 0 then
IsValidEmail = false
exit function
end if
for i = 1 to Len(name)
c = Lcase(Mid(name, i, 1))
if InStr("abcdefghijklmnopqrstuvwxyz_-.", c) <= 0 and not IsNumeric(c) then
IsValidEmail = false
exit function
end if
next
if Left(name, 1) = "." or Right(name, 1) = "." then
IsValidEmail = false
exit function
end if
next
if InStr(names(1), ".") <= 0 then
IsValidEmail = false
exit function
end if
i = Len(names(1)) - InStrRev(names(1), ".")
if i <> 2 and i <> 3 then
IsValidEmail = false
exit function
end if
if InStr(email, "..") > 0 then
IsValidEmail = false
end if
end function