Get value from another #document JavaScript !Doctype

February 4, 2022

How can I get value from another iframe?

When I inspecting the website and I click on this line:

<input type="hidden" name="1" value="q"›

And I type this to the console:

document.getElementsByName("3")[0].value

I can get the value:

‘e’

But if I click outside from iframe, and I check the value I get this result:
VM89205:1 Uncaught TypeError: Cannot read properties of undefined (reading ‘value’)
at :1:49

Looks like I have to click inside if I want get the value. Is it possible to get the value without every time click inside?

<iframe name="frame" id="frame" src="TEST.html?token=asdasdasd" style="display: none;"> ==$0 
    #document
      <html>...</html>
     </iframe>                                                                                    
    <form name="apple" id="apple" method="get" action="test.htm?token=asdasdasd" target="dialog">  <input type="hidden" name="1" value="q"›
      <input type="hidden" name="1" value="q"›
      <input type="hidden" name="2" value="wm> 
      <input type="hidden" name="3" value="e"> 
      <input type="hidden" name="4" value="r"› 
      <input type="hidden" name="5" value="e> 
      <input type="hidden" name="6" value="z"> 
      <input type="hidden" name="7" value>
      <input type="hidden" name="8" value="u"> 
      <input type="hidden" name="9" value="i"> 
      <input type="hidden" name="10" value>

>Solution :

To access an iframe’s content from outside the iframe (provided, it’s not an external domain), use document.getElementById("frame").contentWindow.document.getElementsByName("3")[0].value;