ASP. NET Ajax learning notes (2)-dom

What is Dom? Why study Dom? Dom is a Document Object Model. Borrow a paragraph from w3pop.com :["W3C Document Object Model (DOM) isProgramAnd scripts to dynamically access and update the document content, structure, and style language platform"
W3C Dom provides standard HTML and XML object sets, and has a standard interface to access and operate on them. Dom is divided into different parts (core, XML and HTML) and different versions (DOM 1/2/3)], we mainly learn xml dom, so how do we understand Dom? According to my understanding, Dom is a set of APIs that encapsulate operations on HTML and XML documents. You can use anyProgramming LanguageAnd can be supported on multiple platforms. We can think that Dom programming can be used to manipulate HTML and XML documents, such as adding and deleting nodes in XML documents. In IE, JavaScript can be used to define an xml dom object: var xmldoc = new activexobject ("Microsoft. xmldom"). For specific operations, search for the object on the website.
Why do I need to learn the DOM when learning ASP. NET Ajax? It can be said that the main purpose of learning Ajax is to allow web pages to transmit data asynchronously, while XML is the main data transmission format, so it is impossible to operate XML data without using Dom. In fact, Ajax is a collection of Dom, JavaScript, XHTML, CSS, XML, XSLT, XMLHTTP and other technologies. I learned how to use CSS and XHTML to layout pages, use Dom to operate XML or XSLT data, and use XMLHTTP for asynchronous data transmission. ASP. NET Ajax integrates these scattered individual technologies.