通常来说，这不需要产生错误。您遇到什么错误？那myObject没有定义？如果是这样，只需添加防护措施并检查其是否已定义。例如：

Generally speaking this shouldn't need to yield an error. What's the error you're getting? That myObject isn't defined? If so, just add a safeguard and check if it's defined. Such as:

if (myObject) {
    myObject.width = 315
}

也就是说，您可以通过将其包装在尝试捕获

That said, you can surpress it by wrapping it in a try-catch

try {
    myObject.width = 315;
}
catch(err) {
    // do nothing
}

要查看正在发生的情况，请尝试运行以下代码，并在删除 var myObject = {} 行时查看正在发生的情况。

To see what's happening, try running the following code and see what's happening when you're removing the var myObject = {} line.

var myObject = {}

try {
    myObject.width = 315;
} catch(err) {
    console.log('error');
}

console.log(myObject)