IFRAME contentWindow为空

谁借莪１个温暖的怀抱￠ 2023-02-22 03:39 6阅读 0赞

I like clean code so I do what I can to avoid unwanted JavaScript [global variables][].  I initially thought that `keys(window)` would give me `window` property leaks but that didn't work because browsers returned different results, so I moved on to using an `IFRAME` to compare default window property keys.

我喜欢干净的代码，所以我会尽力避免不必要JavaScript [全局变量][global variables] 。 我最初以为`keys(window)`会给我`window`属性泄漏，但是由于浏览器返回不同的结果而无法正常工作，因此我继续使用`IFRAME`比较默认窗口属性键。

When I first tried this method, I got a lame error about an `IFRAME` element's `contentWindow` property being `null`.  Ugh.  It didn't take long to figure out why:  you need to wait until the `IFRAME` has loaded to get the `contentWindow`:

当我第一次尝试此方法时，我遇到了一个`contentWindow`错误，关于`IFRAME`元素的`contentWindow`属性为`null` 。 啊。 很快就知道了为什么：您需要等到`IFRAME`加载后才能获得`contentWindow` ：

var iframe = document.createElement('iframe');
    iframe.onload = function() {
    	// contentWindow is set!	
    };
    iframe.src = 'about:blank';
    document.body.appendChild(iframe);

Of course you'll want to add the `onload` event before setting the `src`.  If you use the `load` event to check for the `contentWindow` property, you'll be in business!

当然，您需要在设置`src`之前添加`onload`事件。 如果您使用`load`事件检查`contentWindow`属性，那么您就可以做生意！

> 翻译自: [https://davidwalsh.name/iframe-contentwindow-null][https_davidwalsh.name_iframe-contentwindow-null]

[global variables]: https://davidwalsh.name/global-variables-javascript
[https_davidwalsh.name_iframe-contentwindow-null]: https://davidwalsh.name/iframe-contentwindow-null