Question

Basically what i am trying to do is to detect number of frames which are contained within the G+ home page, and off course i do use a content script

The Js file for the extension:

var myIframes;
window.addEventListener('load'
,function()
{
    //If the window location matches the G+ home page
    //Log number of frames contained within it
    if(window.location.href.match("https://plus.google.com/u/0/"))
    {
        console.log('G+ loaded');

        myIframes = document.getElementsByTagName('iframe');
        console.log(myIframes.length);
    }
}
,false);

The o/p log of executing this code is:

G+ loaded

2

Now comes the strange part, when i try to access the myIframes variables length from within the inspector console, i got 8 frames.

So my question is “How come !.”, shouldn’t the myIframes variables stay as it was when it first get evaluated ?

Answer 1

document.getElementsByTagName('iframe') returns a nodeList.

nodeLists are live, they will update when the DOM changes.