未捕获的TypeError：无法读取未定义的属性'contentDocument'

Question

function init() {
    document.getElementById('step1').innerHTML = document.getElementsByTagName('iframe')[0].contentDocument.document.body.innerHTML;
    document.getElementById('code1').value = document.getElementById('google_ads_frame1').src;
    document.technical1.submit();
}

  

o erro se encontra na linha                   document.getElementById'step1 '）的innerHTML = document.getElementsByTagName（' IFRAME'）的 [0] .contentDocument.document.body.innerHTML;

Answer 1

仅使用contentDocument.body代替contentDocument.document.body：

document.getElementById('step1').innerHTML = document.getElementsByTagName('iframe')[0].contentDocument.body.innerHTML;

或contentWindow代替contentDocument：

document.getElementById('step1').innerHTML = document.getElementsByTagName('iframe')[0].contentWindow.document.body.innerHTML;

iframe.contentDocument与iframe.contentWindow.document

相同

HTML: Getting document from IFrame