Alerting Javascript array object shows empty

Question

I am trying to send the JavaScript array to my php , but php gets empty [].
It even shows like that in my browser. I have always sent JSON and had no problem, but now have this format.

I have this example that makes no sense...it's just a code to illustrate the issue:

var blah    = [];
var letters = ['a', 'b', 'c', 'd'];

for (var i = 0; i < letters.length; i++)
{
    blah[letters[i]] = i;
}

Inside firebug DOM it shows as follows:

blah      []
    a      0
    b      1
    c      2
    d      3

When I do

1. alert(blah) ------------------------------- I get empty
2. alert(JSON.stringify(blah)) ----- I get []
3. alert(blah.a) ---------------------------- I get 0

So how can I pass this object to php ? Thanks

Answer 1

Instead of an array, try using an object.

So instead of:

var blah    = [];

Try

var blah    = {};

Answer 2

Arrays are continuously numerically indexed. They do not have strings as key names.
What you want is an object {} , not an array [] .

Answer 3

I have answered this before. Anyway, blah is an array, but you are not using it as array, you are using it as a hashmap. Arrays work with indexes and maps work with keys. Any object in JS can also act like a map. For eg

var obj = new Object();
obj.a = 10;
obj["b"] = 20;

var obj2 = function(){...}
obj2.foo = 10;
obj2.bar = "baz";

Similarly, Array is also and Object and can act like a map. But when you use the array like a map, its array is not utilized to store the elements. They just act like above. So the length of an Array is 0 even though it has properties attached to it.

What you must do is use Array methods like push and pop to populate and retrieve from it.

Answer 4

Can not assign key value collection in array. You need to work on objects:

var obj = {
    key1: value1,
    key2: value2
};

for converting array to string you can use:

var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.toString(); 

with seperator:

var fruits = ["Banana", "Orange", "Apple", "Mango"];
var energy = fruits.join(" and "); 

Here is working Demo

try this:

var blah    = {};
var letters = ['a', 'b', 'c', 'd'];

for (var i = 0; i < letters.length; i++)
{
    blah[letters[i]] = i;
}

alert(JSON.stringify(blah));