唯一识别电脑的好方法是什么？(What's a good way to uniquely identify a computer?)

 在动态创建脚本元素时， 在将元素插入文档之前，不会加载或执行源文件 。 加载脚本是异步的 。 这意味着您的代码执行以下操作： 
 
 
 
 创建脚本元素 
 
 
 分配源属性 
 
 
 将元素放入文档中 
 
 
 开始异步加载源文件 
 
 
 加载后，执行脚本 
 
 
 编辑：感谢您指出设置async属性对脚本的加载行为没有任何影响。 我从来没有真正使用它，并认为它会工作，但它显然没有。 我删除了声称会这样做的部分。 我做了一个例子来说明这一点 。 

When creating a script element dynamically, the source file will not be loaded or executed before the element has been inserted into the document. Loading of a script is asynchronous. This means your code does the following:
 
 
 
Create the script element
 
 
Assign a source attribute
 
 
Place the element into the document
 
 
Start loading the source file asynchronously
 
 
When loaded, execute the script
 
 
Edit: Thanks for pointing out that setting the async property does not have any effect on the loading behaviour of scripts. I never actually used it and assumed it would work, but it apparently does not. I removed the part claiming it would. I made an example to show this.