Question $21(15$ points$)$

Assume the following JavaScript program was interpreted using static$-$scoping rules.

What value of $x$ is displayed in function sub$1?$ Under dynamic$-$scoping rules, what

value of $x$ is displayed in function sub$1?[$Include explanation for your answer$]$

var x;

function sub$1()\{$

document.write$("$x $="+$ x $+"")$;

$\}$

function sub$2()\{$

var x;

x$=10$;

sub$1()$;

$\}$

x$=5$;

sub$2()$;