JavaScript running mechanism: Why JavaScript is single-threaded

This time I will bring you JavaScriptWhy JavaScript is single-threaded in the running mechanism, When using JavaScriptrunning mechanismWhat are the precautions, the following is the actual combat Let’s take a look at the case.

JavaScriptA major feature of the language is single-threading, which means that only one thing can be done at the same time. So why can't JavaScript have multiple threads? This can improve efficiency.

The single thread of JavaScript is related to its purpose. As a browser scripting language, JavaScript's main purpose is to interact with users and manipulate the DOM. This determines that it can only be single-threaded, otherwise it will cause very complex synchronization problems. For example, assuming that JavaScript has two threads at the same time, one thread adds content to a certain DOM node, and the other threaddeletethe node, then which thread should the browser use as the allow?

So, in order to avoid complexity, JavaScript has been single-threaded since its birth. This has become the core feature of this language and will not change in the future.

In order to take advantage of the computing power of multi-core CPUs, HTML5 proposed the Web Worker standard, which allows JavaScript scripts to create multiple threads, but the child threads are completely controlled by the main thread and must not operate the DOM. Therefore, this new standard does not change the single-threaded nature of JavaScript.

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