SyntaxError: missing variable name

SyntaxError: missing variable name (Firefox)
SyntaxError: Unexpected token = (Chrome)

var = "foo";

var description = "foo";

var debugger = "whoop";
// SyntaxError: missing variable name

var x, y = "foo",
var x, = "foo"
var first = document.getElementById('one'),
var second = document.getElementById('two'),
// SyntaxError: missing variable name

var x,
  y = "foo";
var x = "foo";
var first = document.getElementById("one");
var second = document.getElementById("two");

var arr = 1,2,3,4,5;
// SyntaxError: missing variable name

var arr = [1, 2, 3, 4, 5];