// Array
was arr = [1,2,9];
function join(array,sign){
var str = "";
for(var item in array){
console.log(typeof item);//string
console.log(typeof array.length);//number
console.log (item); // 0 1 2 item type String
if(item==array.length-1){
sign = "";
}
str += array[item] + sign;
}
return str;
}
console.log(join(arr,"#"));
join(arr);
// Objects
var obj = {
a:1,
b:2,
c:3,
d:{
a:1,b:2
}
}
for(var prop in obj){
// prop key is that all property names under obj
// each cycle will be paid to prop variable attribute names
console.log(prop,obj[prop]);
}