Uncaught TypeError: Cannot set properties of null

这个错误通常发生在你尝试在 null 值上设置属性时。意味着你正在访问一个不存在的对象或元素。请确保你在设置属性之前正确地初始化了对象，并且对象不是 null。

例如，如果你正在尝试通过以下方式设置一个元素的属性：

var element = document.getElementById('myElement');
element.style.color = 'red';

请确保 `getElementById` 方法返回一个有效的元素，而不是 null。如果元素不存在，你将无法设置它的属性。

你可以通过在设置属性之前添加一些验证来防止此错误的发生，例如：

var element = document.getElementById('myElement');
if (element !== null) {
  element.style.color = 'red';
}

这样，只有当元素存在时才会设置其属性，否则就不会执行任何操作，避免出现 TypeError。

相关问题

Uncaught TypeError: Cannot set properties of null (setting

'innerHTML')

This error message indicates that you are trying to set the innerHTML property of a null value, which is not possible. This usually happens when you are trying to access an element in the DOM that does not exist, or has not been loaded yet.

To fix this error, you should first check that the element you are trying to access exists in the DOM. You can do this by using the document.getElementById() method to retrieve the element by its ID. If the element does not exist, you can create it dynamically using the document.createElement() method.

Additionally, you should make sure that your JavaScript code is executed after the HTML document has been fully loaded. You can do this by placing your script tags at the end of the HTML document, or by using the window.onload event to ensure that your code is executed only after the page has finished loading.

onblur.html:20 Uncaught TypeError: Cannot set properties of null

This error message indicates that you are trying to set a property on a null object. In other words, you are trying to access an element in the document that does not exist.

The error is occurring on line 20 of the onblur.html file, which suggests that there is an issue with the code on that line. Without seeing the code, it is difficult to determine the exact cause of the error.

Here are a few common reasons why this error might occur:

- The element you are trying to access does not exist in the HTML document.
- The element is not yet loaded when the JavaScript code is executed.
- There is a typo in the element ID or class name, causing the code to search for a non-existent element.

To fix the error, you should check the code on line 20 and make sure you are accessing the correct element. You should also ensure that the element exists in the HTML document and is loaded before the JavaScript code is executed. Finally, double-check any IDs or class names to make sure they are spelled correctly.