Empty array

Original - javascript Code function check(){ var a = arr(); alert('number 1 is '+a.num1); alert('number 2 is '+a.num2); alert('a is '+a); alert('length of a is '+a.length); return true; } function arr(){ var ar = new Array(); ar['num1'] = 19.97; ar['num2'] = 19.98; return ar; }

 
function check(){
    var a = arr();
    alert('number 1 is '+a.num1);
    alert('number 2 is '+a.num2);
    alert('a is '+a);
    alert('length of a is '+a.length);
    return true;
}
 
function arr(){
    var ar = new Array();
    ar['num1'] = 19.97;
    ar['num2'] = 19.98;
    return ar;
} 

var myArray=[];
myArray[0]='John';
myArray[1]='Bull';

var myObject={};
myObject['firstname']='John';
myObject['lastname']='Bull';

var length = 0;
for (var i in a)
    length++;

if (typeof a["num1"] != "undefined")
    ...