Differences between BOM and DOM

Differences between BOM and DOM

§ The implementation of various functions of DHTML technology relies on the interaction between client scripts and Web pages output from the browser host and in the host. Such interaction is achieved through the technical means of objects.

§ BOM is the Browser Object Model of Browser. It is an extension API Based on the client Script core. Through this API, you can use scripts to access all aspects of Browser windows and their document objects. BOM is introduced from IE3.0/NS3.0.

§ In bom api, the main explicit features, Web pages, tags, and content of Web browsers are encapsulated into objects, these objects provide access windows, documents, and element objects for members, and implement the object event support mechanism. There is a certain correlation between all BOM objects.

§ Learning BOM technology is mainly to learn how to use BOM objects by using client scripts. Through these encapsulated BOM objects, many DHTML functions can be achieved.

§ BOM technology is not a standardized Web technology, but varies with browsers. This greatly limits the application fields and Development Prospects of DHTML technology.

§ BOM technologies implemented by different browsers are not uniform, which is the main reason for the difference in DHTML technology implementation. Therefore, W3C expands, improves, and optimizes the BOM technology, A new standard for unified technical specifications is developed, that is, DOM (Document Object Model) Document Object Model Technology.

§ DOM technology was initially developed for parsing and controlling XML documents. However, HTML documents can be converted into XHTML documents and DOM technology can be used to access various objects in Web page documents.

§ Currently, W3C has developed three different levels for DOM technical specifications, namely DOM Level 1/2/3. IE5/NS6 fully supports DOM Level 1. Sometimes, some people refer to BOM as DOM Level 0 [which is not officially mentioned by W3C!].

§ The core of DOM technology is to parse the XML (including XHTML) document structure into a tree structure. Each tag is regarded as a Node, and there is a certain relationship between nodes, and access each other through these relationships.

§ DOM technology is closely related to XML technology. It involves complex technical content and is difficult to learn. However, it is helpful to learn DOM technology after mastering BOM technology.

§ DOM technology can be used not only in scripting languages such as JavaScript, but also in heavyweight programming languages such as Java.