<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML xmlns = "http://www.w3.org/1999/xhtml">
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8"/>
<Title> untitled document </title>
</Head>
<Body>
<Div style = "width: 300px; Border: # ff0000 solid 1px;">
<Div style = "width: 200px; float: Left; position: relative; Border: #000000 solid 1px; clear: Left">
<P> shown here </P>
<P> New Div tag </P>
<P> content </P>
</Div>
<Div style = "width: 80px; float: Left; position: relative; Border: # define CC solid 1px; clear: Right"> the content of the new Div label is displayed here </div>
</Div>
</Body>
</Html>
I found that there are quite a few people with the same problem by searching on the Internet, and there are also a lot of methods provided. js and Height = 100% are useful, and I don't think they all work.
I added
<Div style = "clear: both"> </div>
The Code is as follows:
<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML xmlns = "http://www.w3.org/1999/xhtml">
<Head>
<Meta http-equiv = "Content-Type" content = "text/html; charset = UTF-8"/>
<Title> untitled document </title>
</Head>
<Body>
<Div style = "width: 300px; Border: # ff0000 solid 1px;">
<Div style = "width: 200px; float: Left; position: relative; Border: #000000 solid 1px; clear: Left">
<P> shown here </P>
<P> New Div tag </P>
<P> content </P>
</Div>
<Div style = "width: 80px; float: Left; position: relative; Border: # define CC solid 1px; clear: Right"> the content of the new Div label is displayed here </div>
<Div style = "clear: both"> </div>
</Div>
</Body>
</Html>
This will solve the problem.