Question

I have this parent page with title Criatweb,
and an iframe page inside it,
I want to change the display of a div inside the iframe page, but to change only when it’s title is Criatweb.
I tried this in the iframe page but didn’t have success:

<script type="text/javascript">
if (window.parent.document.title == 'Criatweb')
{document.getElementById('customizarsite').style.display = 'none';}    
</script>

Answer 1

The error message means you are calling it before the element is loaded on the page!

It is like walking through a door before opening it. Not going to happen unless you are a ghost.

You need to call it onload or onready or after the element.

<div id="customizarsite">Put the script after me</div>
<script type="text/javascript">
    if (window.parent.document.title == 'Criatweb') {    
        document.getElementById('customizarsite').style.display = 'none';
    }    
</script>