Pragmatic Unit Testing in JavaScript

More often than not, companies completely (and irresponsibly) disregard JavaScript as code that should be unit tested. They might test their back-end code, it may be in C#, Ruby, Java, or even PHP, or just about any other language. But there's a good chance that the front-end code is thoroughly untested. Integration level testing with tools such as Selenium is nice in theory, but way too impractical (you have to set up a server), and particularly slow (loading browsers and computing the recorded actions takes its toll). As such it's rarely part of build processes, and it's run manually (with a single command, but manually nonetheless). So why is that JavaScript gets treated so differently from the rest of languages?