Change iframe form action

[opstabom]

I have to change iframe form action from javascript I load iframe and then write javascipt

var page=window.frames['page'];

alert(page);

var form=page.document.getElementById(id);

form.action="<?php echo HOST."save.php"; ?>";

When i move alert script don't work with alert works fine

 

How to change iframe form action method when iframe loads from javascript