How to pick element inside iframe using document.getElementById

问题

I have a iframe like this

<iframe name=\"myframe1\" id=\"myframe1\" width=\"100%\" height=\"100%\" src=\"a.html\">
<html>
    <head></head>
    <frameset name=\"myframe2\" cols=\"0%, 100%\" border=\"0\" frameBorder=\"0\" frameSpacing=\"0\">
        <frame name=\"page1\" src=\"c.html\" scrolling=\"no\"></frame>
        <frame name=\"page2\" src=\"d.html\" >
            <html>
                <head></head>
                <body id=\"top\">
                    <div id=\"div1\">
                        <div id=\"div2\">
                            <div id=\"div3\">
                                <ul id=\"x\">
                                    <li>a</li>
                                    <li>b</li>
                                </ul>
                            </div>
                        </div>
                    </div>
                </body>
            </html>

        </frame>

    </frameset>
</html>
</iframe>

I want to refer to the element \"x\". I tried in several ways but I couldn\'t find a solution.

回答1:

document.getElementById('myframe1').contentWindow.document.getElementById('x')

Fiddle

contentWindow is supported by all browsers including the older versions of IE.

Note that if the iframe's src is from another domain, you won't be able to access its content due to the Same Origin Policy.

回答2:

use contentDocument to achieve this

var iframe = document.getElementById('iframeId');
var innerDoc = (iframe.contentDocument) 
               ? iframe.contentDocument 
               : iframe.contentWindow.document;

var ulObj = innerDoc.getElementById("ID_TO_SEARCH");

回答3:

(this is to add to the chosen answer)

Make sure the iframe is loaded before you

contentWindow.document

Otherwise, your getElementById will be null.

PS: Can't comment, still low reputation to comment, but this is a follow-up on the chosen answer as I've spent some good debugging time trying to figure out I should force the iframe load before selecting the inner-iframe element.

回答4:

In my case I was trying to grab pdfTron toolbar, but unfortunately its ID changes every-time you refresh the page.

So, I ended up grabbing it by doing so.

const pdfToolbar = document.getElementsByTagName('iframe')[0].contentWindow.document.getElementById('HeaderItems');

As in the array written by tagName you will always have the fixed index for iFrames in your application.

来源：https://stackoverflow.com/questions/14451358/how-to-pick-element-inside-iframe-using-document-getelementbyid

标签

javascript

html

iframe

getelementbyid

frameset