To be honest Perl 5 isn't really like Perl 4. They are quite different languages - Perl 4 didn't have objects, and Perl 5 places heavy emphasis on them.
Up to you to decide when you think it started, but I'd say the current language we think of as "Perl" started with the release of Perl 5.
Most Perl 4 runs under Perl 5, and most Perl 5 written in the early years did not place heavy emphasis on objects. When I started in Perl, it was common to write code in such a way that it would run under either because it might have to.
Today, objects are used heavily. And furthermore the way we write those classes has changed a lot since Moose and friends became popular. As a result most Perl code bases written in the last dozen years look less like early Perl 5 than early Perl 5 looked like Perl 4.
Perl 4 and Perl 5 are more of a continuum than different languages.
It does add up because Perl was released in 80's and became popular in the 90s, when the other newer languages you listed were designed and released. In the early-mid 90's, "CGI"/"CGI scripts" was synonymous with Perl - it was the backend tech
Perl was released in 1987. The languages released in the 90s all stole Perl/Awk's good idea (have an associative array/hash map/dict type as a builtin data type) but had much nicer syntax.
I stuck with Perl even when Ruby came along and offered to be the next best thing because Ruby didn't have a use strict equivalent. Having to declare variables before use is a good thing.
PHP was a reimplementation of Perl by someone who didn't understand why Perl did things the way they did and so ended up creating a vastly inferior language. Other than maintaining some legacy projects, I've not touched PHP in over a decade and I'm glad to avoid it. Perl is a tool I still return to for some tasks (one was a bizarre management request for a spreadsheet of all the Java classes in a large project which took fifteen minutes to create a Perl script to generate and ten of that fifteen minutes was looking at documentation for Perl modules I hadn't used in a long time).
Yes and No. PHP (Perl for Home Pages) main starting point for popularity was that it was easy to make into an Apache module that could be used on shared hosting. Perl's Apache module was a single interpreter for the whole server. Great for business sites and such, not good when you have multiple unrelated users using the same server. PHP was just something that you could turn on and uses on your shared hosting.
According to Wikipedia PHP stands for "Personal Home Page".
Yes, the memory isolation model of mod_php was the crucial factor in beating the competition. With mod_perl you had to write your Perl modules to a specification so that globals were not accessible by other hosts. That was too much of a risk for shared hosting providers. The situation is muddied, however, in that a lot of shared hosts only allow PHP as a cgi which, in theory, puts it on a level playing-field with Perl. However, in practice, Perl only has one PHP-alike templating framework - HTML::Mason - and that requires mod_perl to perform decently. So PHP's other advantage is that its templating engine is simply faster.
As far as i know Java and PHP became popular later in the 90s / early 2000s. Javascript was browser only until 2010, Ruby only became popular after Rails came out mid-2000s. There is a decade gap there.
Depending on how you look at it you are at least a decade too late: we Java folks had the Rhino Javascript engine back in the late 1990ies, and it had an interpreted mode since 1998: https://en.wikipedia.org/wiki/Rhino_(JavaScript_engine)
I think it is even mentioned in the Javascript in a Nutshell book by David Flanagan (I haven't read it since then but I studied that book as I wrote a map rendering system in Javascript back in school in 2005.)
True, I played with Rhino, Jack / JSGI early on, and did a couple projects with Aptana Jaxer around 2009. It was not really an option most developers would even consider, though.
Node came out in 2009, and writing server-side JS was still a fringe practice for a couple more years, so 2010 is me being generous to avoid comments on the exact timeline ;) It really picked up mainstream adoption around 2011-2012.
Was Rhino ever anything other than a minefield that you were essentially pigeonholed into using for compatibility reasons or something similar? I have used it before but only because we had specific technical requirements that demanded we run Javascript on a server-side JVM implementation.
At the end of the 90s Javascript was used to write a part of Dreamweaver and I mean the app itself, not the Javascript/HTML interface. So the language as always existed independently of browser implementations.
