html - execution of some code inside javascript function -

i have div example code in it. i'd execute code after pressing button. here's i've tried:

html

<button onclick="javascript:playcode()"> </button> 

js

function playcode () {      var execcode= "";      (i=1; i<=countcodeline (); i++)          execcode += document.getelementbyid("line"+i).innertext;       var div= document.getelementbyid ("mydiv");      var scr= document.createelement ('script', "");      div.innerhtml= "play() {"+execcode+"}";      div.appendchild(scr);      play(); } 

but doesn't work. how can this?

update: here errors console:

(line 9: pre.appendchild(scr)) uncaught syntaxerror: unexpected token {  (line 10: play()) uncaught typeerror: object not function  

if indeed getting right html execcode, can use

eval(execcode); 

you can check doing simple console.log(execcode) or alert(execcode) verify it's loaded correctly.

however, can guarantee almost very, bad idea. it'd trivial edit dom , insert whatever malicious javascript want.