CSS "the display property and the visibility property"

Question

I still do not understand the main functions of the css code of "display: none; and the visibility property" in a web ? Please help me

Answer 1

Display is CSS's most important property for controlling layout. Every element has a default display value depending on what type of element it is. The default for most elements is usually block or inline. A block element is often called a block-level element. An inline element is always just called an inline element.
1)Block :
div is the standard block-level element. A block-level element starts on a new line and stretches out to the left and right as far as it can. Other common block-level elements are p and form, and new in HTML5 are header, footer, section, and more.
2)Inline :
span is the standard inline element. An inline element can wrap some text inside a paragraph <span> like this </span>without disrupting the flow of that paragraph. The a element is the most common inline element, since you use them for links.
3)None :
Another common display value is none. Some specialized elements such as script use this as their default. It is commonly used with JavaScript to hide and show elements without really deleting and recreating them.
This is different from visibility. Setting display to none will render the page as though the element does not exist. visibility: hidden; will hide the element, but the element will still take up the space it would if it was fully visible.