DataGrid's deep learning notes (2)

 1. DHTML:Dynamic HTML. the traditional html is static. When it is loaded into a browser, it is only like a screen, but it does not change. Dynamic Html means that the web page responds to users, that is, dynamic Html can be changed automatically.

First, it can track every element on the page, from the smallest "H6" title and "HR" Horizontal ruler, to all elements in the form.
Secondly, DHTML also requires a method to control all elements in a document that need to be controlled, which can be completed through some scripting languages, such as javascript or vbscript, the scripting language will embed relevant information into each element on the page and view their set values to make the expected changes.

In short, DHTML is not related to server-oriented scripts, javaapplet, or animated GIF images. All these operations can be done by yourself. Besides changing the page content, you do not need to access the server. After the page is downloaded, DHTML can process the page elements and change the page layout, content, and position. And continuously provide the results to users.

Currently, there are no uniform standards for DHTML. Microsoft, Netscape, and w3c are incompatible. Sometimes when you go to some sites, you will find that it prompts you to use a browser such as XX, that is, this site may have incompatible DHTML.

2.DOM:The World Wide Web Consortium (W3C) has developed a platform and language-independent specification, that is, the Document Object Model DOM (Document Object Model ).
DOM combines HTML, CSS (Cascading Style Sheets), and scripting to form an interoperability model that can be achieved by one or more people. Netscape and Microsoft both proposed DOM implementation suggestions to W3C: Use Dynamic HTML, that is, DHTML (Dynamic HTML) to solve the problem.

3. CSS itself has no interaction function. To achieve interaction, you must combine the CSS-defined objects with the document model (DOM) to convert Web documents into DHTML documents. DOM provides a way for scripting to access elements on pages. The object models supported by Microsoft and Netscape are somewhat different.
In Microsoft's model, the scripting language can access all elements on the HTML page. all elements are reflected as objects in document. all. The following program section is used to write all the elements on the page:
For (I = 0; I <document. all. length; I ++> 〉
{
Document. write (document. all [I]. tagName + "\ n ");
}

In the Netscape model, the scripting language can access elements of a specific set on the HTML page, such as the content in the <layer> label. The following program section is used to write the names of all layers on the page:
For (I = 0; I <document. layers. length; I ++> 〉
{
Document. write (document. layers [I]. name + "\ n ");
}