In-depth explanation of non-paired tags of document. write () and HTML4.01 _ basic knowledge

This article describes the non-paired tags of document. write () and HTML4.01 in detail. For more information, see (1) unpaired tags in HTML4.01:

Annotation label:

Strictly speaking, it is not an HTML Tag: Document declaration tag

Set the page metadata: Tag

Set the relative directory (such as the root directory) of all links on the webpage:Tag

Line feed:

Horizontal line:

Image:

Form Element

Label that defines the attributes of one or more columns in a table

Defines the labels of a window of the framework.

Define the relationship between documents and external resources: Link tag

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(2) document. write ()

1. This method is part of level 0 DON. Call this method to create a new output stream with the content of this parameter;

2. When calling the top-level script element, that is, when calling the window. onload event handle or a place other than the defer function, this method will output this content when the parser parses it. In this case, the previous documents are not overwritten.

3. When calling the window. onload event handle or defer function, the output content of this method overwrites the current document stream. In this case, the previous document is overwritten.

4. When this method is called consecutively, the output content is in the same output stream. When the output stream document. close () is closed before the method is called, this method overwrites the previous document stream. The document. open () method creates a new output stream to overwrite the previous document stream.