Having to pick a delimiter that won't occur in your data is bad. Instead, escape the data such any instance of you your delimiter is removed or distinguishable from an actual delimiter.

In this case, it's easy to remove commas by URI escaping the data before joining the fields.

At the client, (My syntax might be off) 

list_items.value = list_items
                   .map(function (v) { return encodeURIComponent(v) })
                   .join(',');

[download]

At the server, 

use URI::Escape qw( uri_unescape );

my @list_items = map { uri_unescape($_) }
                 split(/,/, $cgi->param('list_items'));

[download]

In reply to Re^5: Getting all values from a CGI list box by ikegami
in thread Getting all values from a CGI list box by rashley

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