One var per function in JavaScript?

Question

I\'ve been using JSLint to make me feel bad about my JavaScript. It is great, by the way. There is one check that I don\'t quite understand and I\'d like your views, please.

Answer 1

The lack of block scope explains the code below:

var a = 1;
if (something) {
    var a = 2;
}

alert(a); // Alerts "2"

In most C-style (as in syntax) languages, the var a = 2 definition would define 'a' only for the scope of the if block. Using a single var statement at the top of the function helps to avoid this quirk of Javascript, which is not always as obvious as the above, and would be unexpected to C/C#/Java programmers.