HTML5 seventh day notes

HTML5’s new tag H5 attaches great importance to semantics

1aa9e5d373740b65a0cc8f0a02150c53ab946e7546ab66a280dd9c9f9310ecd5 Header (equivalent to div, which defaults to the effect of div in browsers that are not compatible with H5)

c787b9a589a3ece771e842a6176cf8e944f9630a3d507ae7532760da37622b0f

c37f8231a37e88427e62669260f0074d84122da5b51c58ef54d7045814144010

The block-level element has no width after it is floated, and you need to add width to it.

background:none;Clear the background image;

Positioning:

position(position):

static:static

fixed: Fixed positioning (changed relative to the browser) does not retain its own position

relative: Relative positioning (changed relative to itself) retains its own position, generally used together with absolute positioning.

absolute: Absolute positioning (changed relative to the parent element) does not retain its position,

left:20px/50%

top: 20px/50%

bottom:20px/50%

right:20px/50%

When an element is absolutely positioned, relative positioning must be set for its parent element.

When there are positioned relationship elements, there is a cascading relationship.

z-index: Set the cascading relationship

z-index:-0 1 2 3 ...99999 (the larger the value, the more it will be displayed on the upper layer)

Display mode of elements

display:block;/inline;/inline-block;/none

display:block The default display mode of block-level elements

display:inline The default display of inline elements Mode

display:inline-block The default display mode of inline block-level elements

display:none hides the label. Does not take up space

visibility:hidden Hide takes up space

Navigation drop-down menu production

Drop-down menu

<nav class="nav">
<ul>
<li><a href="#">主页</a></li>
<li><a href="#">新闻</a>
<div>
<p>本地</p>
<p>国内</p>
<p>国际</p>
<p>政府</p>
</div> 
</li>
<li><a href="#">娱乐</a></li>
<li><a href="#">军事</a></li>
<li><a href="#">头条</a></li>
</ul> 
</nav>
li div{
display: none;
position: absolute;
background:darkgreen;
}
li:hover div{
display: block;
}
.nav ul{
position: relative;
}

The above is HTML5 The content of the notes on the seventh day, for more related content, please pay attention to the PHP Chinese website (www.php.cn)!