javascript - Google Chrome Console Copying Variables -

i came across interesting behavior in google chrome's console when "copying" variable.

try following on "fresh" chrome console one line @ time:

var = "string";

var copy = a;

copy.length; //returns uncaught typeerror: cannot read property 'length' of undefined

copy happens unlucky choice variable name in console but, curiously, if reassign twice work (try following on new "fresh" console):

var = "string";

var copy = a;

var copy = a; //declare twice

copy.length; //6

is there reason why works way in console? on 64-bit 43.0.2357.130

JVParth