Know if a DOM object is dead

Question

I am working with a variable containing a webpage element such as a button. However, sometimes I get the error "Can't access to a dead object" because the page containing the element has changed since the moment I saved it.

I would like to know a way to check if an element is dead or not, I tried :

if(element)
    alert("Do something");

but it doesn't work as expected.

how about `if(!!element)`? this will force `element` to be truthy — OnesimusUnbound, Aug 23 '13 at 11:38
FYI to people who post answers, this is a [Firefox protection](https://blog.mozilla.org/addons/2012/09/12/what-does-cant-access-dead-object-mean/) — user247702, Aug 23 '13 at 11:44
And to people who suggest duplicates: the question is about DOM objects, not JavaScript objects. — JJJ, Aug 23 '13 at 11:46

score 0 · Accepted Answer · edited May 23 '17 at 11:44

0

copied from How to check if element exists in the visible DOM?

   var elementInDocument = function(element) {
        while (element = element.parentNode) {
            if (element == document) {
                return true;
            }
        }
        return false;
    }

You can use it like:

if(elementInDocument(element))
    alert("Do something");

edited May 23 '17 at 11:44

Community

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answered Aug 23 '13 at 11:38

tobspr

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It's quite obvious finally, I just have to check if the element is present in the DOM. – user2302725 Aug 23 '13 at 12:43

score 0 · Answer 2 · answered May 19 '14 at 20:37

//eval it in your mozilla-browser space

var dc = content.document;
content.document.location.reload();
setTimeout(function(){ 
  try{ 
    dc.parentNode;
  }catch(e){
    if (e.message.indexOf(' dead ')!=-1){
        alert('REALY DEAD!');
    }
} }, 1000);

it is a test of dead (in try..catch block) in my moz extension projects.

Know if a DOM object is dead

2 Answers2