I think it's better to flip the question around: I make my living writing single-page web apps in JavaScript. These days, everything I do, even on the server, is in JavaScript. What does Perl do a hundred times better than the latest in the JavaScript universe (ES6, Meteor, node.js, etc.)? If it doesn't, that right there is your answer.
There is not a single (well known) reason for using Perl. Even if it's 10% better and faster than any other language without a unique selling point the cost of switching is just too high in most cases.