Several lessons about CSS

(1) The DIV block cannot be written even if the content is empty.

<Div id = "someid" class = "smomeclass"/>

Otherwise, CSS considers that the DIV is not closed, causing a parsing error. Which of the following statements is true?

<Div id = "someid" class = "smomeclass"> </div>

If you use the xmldocument class of FCL to write an XML file, the DIV of the empty content will be written as an error. To avoid this error, you can add a hidden display content to the div, for example, <HR style = "display: none"/>.

 

(2) Why does the same CSS Tag play a role in some HTML files but not in another HTML file. For example, cursor: Hand. This is because of the html version, which corresponds to the lifecycle of the document. If it is an old version, it works. If it is a new version of xhtml1.0, it needs to be changed to cursor: pointer.

 

(3) The display attribute of the element not displayed is not necessarily none, but may be null. For example

. Myclass {display: none ;}

<Div class = "myclass"> something </div>

 

Although something is not displayed, It is empty when the style. Display attribute is obtained through JavaScript.