利用全局数组

I want to use the values that I get from a request, but the response object is a local variable (an array). Therefore I create this global array:

<script type="text/javascript">
    var response = [];

as you see, right under the script opening tag, so it is global. Then in the function where I have the response I added this:

jsonResponse.forEach(function(element){
    response[element.size] = element.id;
});

And then added this, with the purpose to make use of the values that I've got in my global var from the response object:

getIdOfProductBySize: function() {
        var selectedIndex = document.getElementById('dropdown_options').value;
        for (var key in response) {
            if (key != selectedIndex) { 
                continue; 
            } else { 
                return response[key]; 
            }
        }   
    }

Doesn't work, so I started going step by step (of the order I add the new things) and I noticed that the script breaks after the 2nd thing that I add (where the forEach is).

Maybe I am not declaring the global variable correctly, or maybe I cannot access it this way, or maybe I don't assign the values to it in the correct way, I don't know, so I am asking if someone can give me a hint how to make use of all this working together?

response[element.id] = element.size;

Try this one, i believe element.size returns the actual size of an element and is not what you want to use as index in an array.

Looks like you're going to need a two dimensional array.

Looks to me like your "key" value is undefined.

before:

for (var key in response) {

try:

var k=response.whatever;

If that makes sense?