We have 400 to 500 hundred emails, when we concatenate them and put them in mailto: it does not work; the browser automatically adds "..." in between emails and thus clicking the link does not work.
<a href='mailto:one@email.com,two@email.com....400@email.com'>open emails</a>
Is there a maximum length on the mailto: attribute? Is there any other way I can open multiple emails?
Just to add a bit more detail... What RFC 1738 actually says is
A mailto URL takes the form:
mailto:<rfc822-addr-spec>
where <rfc822-addr-spec> is (the encoding of an) addr-spec, as specified in RFC 822 [6].
and while RFC2822 may have subsumed RFC822, RFC2822 does not change the addr-spec specification (section 3.4.1) as
addr-spec = local-part "@" domain
More specifically, RFC 1738 does not say the URL takes the form of an RFC822 Address Specification but directly says the encoding of an addr-spec.
It is true that in RFC2822, section 3.4 Address Specification, the definition of group is modified from, in RFC822,
group = phrase ":" [#mailbox] ";"
mailbox = addr-spec ; simple address
/ phrase route-addr ; name & addr-spec
to
group = display-name ":" [mailbox-list / CFWS] ";"
display-name = phrase
mailbox-list = (mailbox *("," mailbox)) / obs-mbox-list
mailbox = name-addr / addr-spec
which does allow multiple addr-specs, but again, the definition of an addr-spec itself remains unchanged.
I would conclude, then, that while it might work, it is not officially supported.