Question

we have 400 to 500 hundred emails, when we concatenate them and put them in mailto: it does not work, browser automatically adds “…” in between emails and clicking link does not work.

<a href='mailto:[e-mail],[e-mail][e-mail]'>open emails</a>

Is there a maximum length on mailto: attribute ? is there any other way i can open multiple emails ?

Answer 1

Just to add a bit more detail… What RFC 1738 actually says is

A mailto URL takes the form:

    mailto:<rfc822-addr-spec>

where 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.