Why do we need to use one "var" to define many variables?

Question

I defined some variables in Javascript:

var aaa = "aaa";
var bbb = "bbb";
var ccc = "ccc";

But my friend says it’s better to define them as:

var aaa = "aaa",
    bbb = "bbb",
    ccc = "ccc";

Because JsLint will report errors in my code.

I am not sure why we should do this as the second one, since I found that my version is better viewed if the value is very large, for example:

var aaa = {
             some1 : 111,
             some2 : 222
          };
var bbb = {
             some1 : 111,
             some2 : 222
          };

Answer 1

In JavaScript, there is no block region, but only level regions. So, if you use several operators var, developers who come from other languages ​​may not feel the difference. For instance,

var numbers = [];

for (var i = 0; i < 10; i += 1) {
    numbers.push(i);
}

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