google-chrome - Firefox console getElementBy doesn't work

Question

Can someone tell me why when i run

document.getElementsByTagName('img')[0]

in chrome's console shows what I want and doing the same on firefox does not?

标签： google-chromefirefox

Answer 1

After some research I found out I was doing it totally wrong as I would have to load the iframe first and then access it. I wrongly thought that this would be done automatically by the browser.