for loop to build an array possible?

Can I use a for loop to build an array?

 

sure;

var r = [];
for (var i=0; i<10; i++) {
r = i+10;
};

 

btw; arrays are nested objects and functions too;

var arr = {
  someName : {
     id : 3,
     value : 4
  },
  someOtherName : {
     id : 4,
     value : 5
  }
};
var searchValue = 4; //or 5
for (var item in arr) {
  var itemData = arr[item];
  if (itemData.value==searchValue) alert ('ID '+itemData.id+' has value '+searchValue);
}

Code (markup):

theres a significant difference between var arr = [], and var arr = {}. {} creates an object, [] creates an indexed array (from 0 to length-1)