Way back in the mid 90s the company I worked for did a lot of server-side Javascript work using Netscape's Livewire server. While there was a set of Javascript objects available for string manipulation, object creation and such, it still came down to doing things like
client.write("<html><body><p>Some variable = " + serverobj.prop1 + "</p></body></html>\n");
I don't remember it being that speedy, either.