Shulou(Shulou.com)06/02 Report--

How to understand the various types of JavaScript relationship, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain for you in detail, people with this need can come to learn, I hope you can gain something.

This diagram comes from page P184, Chapter 3 of the essence and programming practice of the JavaScript language. Recently in the second edition, this picture has been redone, what is needed can be compared.

In addition, supplement the concepts used in the figure:

1. The difference between built-in (Build-in) objects and native (Naitve) objects is that the former is always a subset of the engine initialization phase and is a subset of the latter, while the latter includes some objects that are dynamically created during operation.

2. Engine extension objects are not a large collection, and generally speaking, they are also native objects of the engine (but not native objects of the ECMA specification).

3. The host object is not the native object of the engine, but the object registered to the JavaScript engine by the host framework through some mechanism.

4. Some hosts refer to the objects / constructors they provide as "native objects". For example, Internet Explorer 7 calls the XMLHttpRequest () it provides native-as opposed to objects created by methods such as "new ActiveXObject ('Microsoft.XMLHTTP')" in earlier versions of it. In this case, the reader should note the difference between the "host's native object" and the "engine's native object".

Is it helpful for you to read the above content? If you want to know more about the relevant knowledge or read more related articles, please follow the industry information channel, thank you for your support.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.