experiment on core javascript concepts in console.

scope of var in javascript

http://stackoverflow.com/questions/500431/javascript-variable-scope

null != undefined

false

null !!= undefined

SyntaxError: Unexpected token !

null !== undefined

true

null == undefined

true

null === undefined

false

null != undefined

false

null !== undefined

true

!!0

false

!0

true

!1

false

!!1

true

var csss = "444px";

undefined

console.log(css);

ReferenceError: css is not defined

console.log(csss);

444px VM470:2

undefined

console.log(csss.replace("px","rr"));

444rr VM471:2

undefined

csss.replace("px","rr");

"444rr"

csss

"444px"

var evt = "onmousedown";

undefined

evt.length

11

var evt = ["onmousedown"];

undefined

evt.length

1

document["onmousedown"] = function(){alert("a")};

function (){alert("a")}