These days I write PHP code infrequently enough that my JavaScript knowledge is starting to get in the way. I learned PHP years before I ever touched JavaScript, but the syntaxes are similar enough that I keep trying to use the var keyword or assign functions to variables. (Even though I’ll probably never start a major project in PHP ever again, I enjoy using the language — it was my first real programming language, and without it I probably wouldn’t be doing what I do today.)