JavaScript was developed in collaboration with Netscape and Sun. When JavaScript 1.0 was released, Netscape Navigator dominated the browser market. When Microsoft launched IE3, it released its own VBScript language and released a version of JavaScript under the name of JScript, which quickly caught up with Netscape. Faced with Microsoft's competition, Netscape and Sun jointly standardized the JavaScript language with ECMA (European Association of Computer Manufacturers), and the ECMAScript language emerged, which is another name for the same language.
DOM is a set of methods to abstract and conceptualize the content of a document. Netscape Navigator 4 was released in June 1997, and IE4 was released in October of the same year. Both browsers have made many improvements to their earlier versions, greatly extending the DOM, allowing a significant increase in functionality that can be done with JavaScript. Web designers have also begun to come into contact with a new term: DHTML (dynamic HTML).
DHTML is not a new technology, but a term that describes the combination of HTML, CSS and JavaScript technologies. Unfortunately, NN 4 and IE 4 browsers use two incompatible DOMs. This leads to a ridiculous situation: programmers must know what browser environment they will run when writing DOM script code, so in actual work, many scripts have to be written twice, once Netscape Navigator and the other time IE. At the same time, programmers must write some code to find out which browser is running on the client. DHTML opens up a new world full of opportunities, but those who want to enter it find it a world full of suffering. Therefore, it didn't take long for the evaluation of this technology to become "propaganda stunt" and "hard to achieve".
While browser manufacturers are launching a marketing war with DOM as a weapon, W3C has launched a standardized DOM based on everyone's advantages. It is gratifying that Netscape, Microsoft and some other browser manufacturers can also set new standards with the W3C and complete the "DOM Level 1" in October 1998.
W3C defines DOM as: "An interface that is independent of the system platform and programming language, through which programs and scripts can dynamically access and modify the content, structure and style of a document." The standardized DOM launched by W3C far exceeds the various proprietary DOMs launched by the respective browser manufacturers in many aspects such as independence and scope of application.
Today almost all browsers have built-in DOM support. We have witnessed the craze for learning DOM scripting triggered by asynchronous data transmission technology (Ajax). How can many new features of HTML5 DOM not make people think about the future of the Web?
The above is my post-reading summary of the first chapter of "JavaScript DOM Programming Technology" (2nd Edition), and understand the development history of javascript.