Dreamweaver is good but the difference between that or using just a simple text editor (including those that have color markup) is the fact that Dreamweaver costs money and is supported. Support might not mean a lot to most people but there are a lot of plugins and code snippets you can download for Dreamweaver that make the job easier. Having Dreamweaver handle all of the JavaScript is definitely worth it. More importantly, if you are doing freelance work, you should have a licenced version of some software recognized by your clients. There's plenty of arguments against buying something, but it's more about professionalism, and such software can be helpful when developing A LOT of different websites.