Ext JS 4.2 add tree node

HTML

<link rel="stylesheet" href="http://cdn.sencha.io/ext-4.2.0-gpl/resources/css/ext-all.css">
<div id="treeList"></div>

JavaScript

function min(a,b) {
 var s =	Math.sign(a - b);
 return s == -1? a : b ;

};
alert(min(35,30))