第三周筆記

創作者使用平台，https://creativecommons.org/choose/

<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/"><img alt="創用 CC 授權條款" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" /></a><br />本著作係採用<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">創用 CC 姓名標示-非商業性-相同方式分享 4.0 國際 授權條款</a>授權.

CSS

語法，ex:h1{color: yellow;text-align: right;font-size: 12px}

<!DOCTYPE html>
<html>
<head>
<style>
p {
  color: red;
  text-align: center;
} 
</style>
</head>
<body>

<p>Hello World!</p>
<p>These paragraphs are styled with CSS.</p>

</body>
</html>

選擇器

基本

<!DOCTYPE html>
<html>
<head>
<style>
p {
  text-align: center;
  color: red;
} 
</style>
</head>
<body>

<p>Every paragraph will be affected by the style.</p>
<p id="para1">Me too!</p>
<p>And me!</p>

</body>
</html>

id 選擇器(特定且通常一個)

<!DOCTYPE html>
<html>
<head>
<style>
#para1 {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>

</body>
</html>

類選擇器(特定但可多個)

<!DOCTYPE html>
<html>
<head>
<style>
.center {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<h1 class="center">Red and center-aligned heading</h1>
<p class="center">Red and center-aligned paragraph.</p> 

</body>
</html>

複合型

<!DOCTYPE html>
<html>
<head>
<style>
p.center {
  text-align: center;
  color: red;
}
</style>
</head>
<body>

<h1 class="center">This heading will not be affected</h1>
<p class="center">This paragraph will be red and center-aligned.</p> 

</body>
</html>

使用方式

外部 CSS 內部 CSS 內聯 CSS

註釋

CSS 註釋放置在style元素內，以以下開頭/和結尾/

<!DOCTYPE html>
<html>
<head>
<style>
p {
  color: red; /* Set text color to red */
}
</style>
</head>
<body>

<h2>My Heading</h2>

<!-- These paragraphs will be red -->
<p>Hello World!</p>
<p>This paragraph is styled with CSS.</p>
<p>HTML and CSS comments are not shown in the output.</p>

</body>
</html>

背景

背景顏色

<!DOCTYPE html>
<html>
<head>
<style>
h1 {
  background-color: green;
}

div {
  background-color: lightblue;
}

p {
  background-color: yellow;
}
</style>
</head>
<body>

<h1>CSS background-color example!</h1>
<div>
This is a text inside a div element.
<p>This paragraph has its own background color.</p>
We are still in the div element.
</div>

</body>
</html>

背景透明度

opacity

<!DOCTYPE html>
<html>
<head>
<style>
div {
  background-color: green;
}

div.first {
  opacity: 0.1;
}

div.second {
  opacity: 0.3;
}

div.third {
  opacity: 0.6;
}
</style>
</head>
<body>

<h1>Transparent Box</h1>
<p>When using the opacity property to add transparency to the background of an element, all of its child elements become transparent as well. This can make the text inside a fully transparent element hard to read:</p>

<div class="first">
  <h1>opacity 0.1</h1>
</div>

<div class="second">
  <h1>opacity 0.3</h1>
</div>

<div class="third">
  <h1>opacity 0.6</h1>
</div>

<div>
  <h1>opacity 1 (default)</h1>
</div>

</body>
</html>

RGBA

<!DOCTYPE html>
<html>
<head>
<style>
div {
  background: rgb(0, 128, 0);
}

div.first {
  background: rgba(0, 128, 0, 0.1);
}

div.second {
  background: rgba(0, 128, 0, 0.3);
}

div.third {
  background: rgba(0, 128, 0, 0.6);
}
</style>
</head>
<body>

<h1>Transparent Box</h1>
<p>With opacity:</p>

<div style="opacity:0.1;">
  <h1>10% opacity</h1>
</div>

<div style="opacity:0.3;">
  <h1>30% opacity</h1>
</div>

<div style="opacity:0.6;">
  <h1>60% opacity</h1>
</div>

<div>
  <h1>opacity 1</h1>
</div>

<p>With RGBA color values:</p>
<div class="first">
  <h1>10% opacity</h1>
</div>

<div class="second">
  <h1>30% opacity</h1>
</div>

<div class="third">
  <h1>60% opacity</h1>
</div>

<div>
  <h1>default</h1>
</div>

<p>Notice how the text gets transparent as well as the background color when using the opacity property.</p>

</body>
</html>

背景圖片

頁面的背景

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("paper.gif");
}
</style>
</head>
<body>

<h1>Hello World!</h1>

<p>This page has an image as the background!</p>

</body>
</html>

為特定元素設置背景

<!DOCTYPE html>
<html>
<head>
<style>
p {
  background-image: url("paper.gif");
}
</style>
</head>
<body>

<h1>Hello World!</h1>

<p>This paragraph has an image as the background!</p>

</body>
</html>

背景重複

水平重複(此為x，若為垂直重複用y)

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("gradient_bg.png");
  background-repeat: repeat-x;
}
</style>
</head>
<body>

<h1>Hello World!</h1>
<p>Here, a background image is repeated only horizontally!</p>

</body>
</html>

不重複

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("img_tree.png");
  background-repeat: no-repeat;
}
</style>
</head>
<body>

<h1>Hello World!</h1>
<p>W3Schools background image example.</p>
<p>The background image is only showing once, but it is disturbing the reader!</p>

</body>
</html>

背景位置

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("img_tree.png");
  background-repeat: no-repeat;
  background-position: right top;
  margin-right: 200px;
}
</style>
</head>
<body>

<h1>Hello World!</h1>
<p>W3Schools background no-repeat, set position example.</p>
<p>Now the background image is only shown once, and positioned away from the text.</p>
<p>In this example we have also added a margin on the right side, so the background image will never disturb the text.</p>

</body>
</html>

背景附件

指定應固定背景圖像

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("img_tree.png");
  background-repeat: no-repeat;
  background-position: right top;
  margin-right: 200px;
  background-attachment: fixed;
}
</style>
</head>
<body>

<h1>The background-attachment Property</h1>

<p>The background-attachment property specifies whether the background image should scroll or be fixed (will not scroll with the rest of the page).</p>

<p><strong>Tip:</strong> If you do not see any scrollbars, try to resize the browser window.</p>

<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>
<p>The background-image is fixed. Try to scroll down the page.</p>


</body>
</html>

指定背景圖像應與頁面的其餘部分一起滾動

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background-image: url("img_tree.png");
  background-repeat: no-repeat;
  background-position: right top;
  margin-right: 200px;
  background-attachment: scroll;
}
</style>
</head>
<body>

<h1>The background-attachment Property</h1>

<p>The background-attachment property specifies whether the background image should scroll or be fixed (will not scroll with the rest of the page).</p>

<p><strong>Tip:</strong> If you do not see any scrollbars, try to resize the browser window.</p>

<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>
<p>The background-image scrolls. Try to scroll down the page.</p>

</body>
</html>

背景速記

使用速記屬性在一個聲明中設置背景屬性

<!DOCTYPE html>
<html>
<head>
<style>
body {
  background: #ffffff url("img_tree.png") no-repeat right top;
  margin-right: 200px;
}
</style>
</head>
<body>

<h1>The background Property</h1>

<p>The background property is a shorthand property for specifying all the background properties in one declaration.</p>

<p>Here, the background image is only shown once, and it is also positioned in the top-right corner.</p>

<p>We have also added a right margin, so that the text will not write over the background image.</p>

</body>
</html>

邊框 border

基礎

dotted - 定義一個虛線邊框
dashed - 定義虛線邊框
solid - 定義一個實心邊框
double - 定義雙邊框
groove- 定義一個 3D 凹槽邊界。效果取決於邊框顏色值
ridge- 定義 3D 脊狀邊框。效果取決於邊框顏色值
inset- 定義 3D 內嵌邊框。效果取決於邊框顏色值
outset- 定義 3D 起始邊界。效果取決於邊框顏色值
none - 定義無邊框
hidden - 定義一個隱藏的邊框

<!DOCTYPE html>
<html>
<head>
<style>
p.dotted {border-style: dotted;}
p.dashed {border-style: dashed;}
p.solid {border-style: solid;}
p.double {border-style: double;}
p.groove {border-style: groove;}
p.ridge {border-style: ridge;}
p.inset {border-style: inset;}
p.outset {border-style: outset;}
p.none {border-style: none;}
p.hidden {border-style: hidden;}
p.mix {border-style: dotted dashed solid double;}
</style>
</head>
<body>

<h2>The border-style Property</h2>
<p>This property specifies what kind of border to display:</p>

<p class="dotted">A dotted border.</p>
<p class="dashed">A dashed border.</p>
<p class="solid">A solid border.</p>
<p class="double">A double border.</p>
<p class="groove">A groove border.</p>
<p class="ridge">A ridge border.</p>
<p class="inset">An inset border.</p>
<p class="outset">An outset border.</p>
<p class="none">No border.</p>
<p class="hidden">A hidden border.</p>
<p class="mix">A mixed border.</p>

</body>
</html>

邊框顏色

用border-color

邊框寬度

用border-width

邊界邊

工作原理

如果border-style屬性有四個值：

邊框樣式：虛線實心雙虛線；頂部邊框是虛線右邊框是實心的底部邊框是雙重的左邊框是虛線如果該border-style屬性具有三個值：

邊框樣式：虛線實心雙；頂部邊框是虛線左右邊框是實心的底部邊框是雙重的如果border-style屬性有兩個值：

邊框樣式：虛線實線；頂部和底部邊框是虛線左右邊框是實心的如果border-style屬性只有一個值：

邊框樣式：虛線；所有四個邊框都是虛線

圓角邊框

<!DOCTYPE html>
<html>
<head>
<style>
p.normal {
  border: 2px solid red;
}

p.round1 {
  border: 2px solid red;
  border-radius: 5px;
}

p.round2 {
  border: 2px solid red;
  border-radius: 8px;
}

p.round3 {
  border: 2px solid red;
  border-radius: 12px;
}
</style>
</head>
<body>

<h2>The border-radius Property</h2>
<p>This property is used to add rounded borders to an element:</p>

<p class="normal">Normal border</p>
<p class="round1">Round border</p>
<p class="round2">Rounder border</p>
<p class="round3">Roundest border</p>

</body>
</html>

邊距 margin

基礎原理類似於border，但其元素在border之外

<!DOCTYPE html>
<html>
<head>
<style>
div {
  margin: 70px;
  border: 2px solid #4CAF50;
}
</style>
</head>
<body>

<h2>CSS Margins</h2>
<div>This element has a margin of 70px.</div>

</body>
</html>

margin collapse

元素的頂部和底部邊距有時會折疊為一個邊距，該邊距等於兩個邊距中最大的一個。

這不會發生在左右邊距上！只有頂部和底部邊距！

<!DOCTYPE html>
<html>
<head>
<style>
h1 {
  margin: 0 0 50px 0;
}

h2 {
  margin: 20px 0 0 0;
}
</style>
</head>
<body>

<p>In this example the h1 element has a bottom margin of 50px and the h2 element has a top margin of 20px. So, the vertical margin between h1 and h2 should have been 70px (50px + 20px). However, due to margin collapse, the actual margin ends up being 50px.</p>

<h1>Heading 1</h1>
<h2>Heading 2</h2>

</body>
</html>

填充 padding

用於在任何定義的邊框border內圍繞元素內容創建空間

寬度和長度

height和width屬性用於設置元素的高度和寬度。 max-width屬性用於設置元素的最大寬度。

<!DOCTYPE html>
<html>
<head>
<style>
div {
  max-width: 500px;
  height: 100px;
  background-color: powderblue;
}
</style>
</head>
<body>

<h2>Set the max-width of an element</h2>

<div>This div element has a height of 100px and a max-width of 500px.</div>

<p>Resize the browser window to see the effect.</p>

</body>
</html>

大綱 outline

<!DOCTYPE html>
<html>
<head>
<style>
p {outline-color:red;}

p.dotted {outline-style: dotted;}
p.dashed {outline-style: dashed;}
p.solid {outline-style: solid;}
p.double {outline-style: double;}
p.groove {outline-style: groove;}
p.ridge {outline-style: ridge;}
p.inset {outline-style: inset;}
p.outset {outline-style: outset;}
</style>
</head>
<body>

<h2>The outline-style Property</h2>

<p class="dotted">A dotted outline</p>
<p class="dashed">A dashed outline</p>
<p class="solid">A solid outline</p>
<p class="double">A double outline</p>
<p class="groove">A groove outline. The effect depends on the outline-color value.</p>
<p class="ridge">A ridge outline. The effect depends on the outline-color value.</p>
<p class="inset">An inset outline. The effect depends on the outline-color value.</p>
<p class="outset">An outset outline. The effect depends on the outline-color value.</p>

</body>
</html>

組合器

後代選擇器（空格）

<!DOCTYPE html>
<html>
<head>
<style>
div p {
  background-color: yellow;
}
</style>
</head>
<body>

<h2>Descendant Selector</h2>
<p>The descendant selector matches all elements that are descendants of a specified element.</p>

<div>
  <p>Paragraph 1 in the div.</p>
  <p>Paragraph 2 in the div.</p>
  <section><p>Paragraph 3 in the div.</p></section>
</div>

<p>Paragraph 4. Not in a div.</p>
<p>Paragraph 5. Not in a div.</p>

</body>
</html>

子選擇器 (>)

<!DOCTYPE html>
<html>
<head>
<style>
div > p {
  background-color: yellow;
}
</style>
</head>
<body>

<h2>Child Selector</h2>
<p>The child selector (>) selects all elements that are the children of a specified element.</p>

<div>
  <p>Paragraph 1 in the div.</p>
  <p>Paragraph 2 in the div.</p>
  <section><p>Paragraph 3 in the div.</p></section> <!-- not Child but Descendant -->
  <p>Paragraph 4 in the div.</p>
</div>

<p>Paragraph 5. Not in a div.</p>
<p>Paragraph 6. Not in a div.</p>

</body>
</html>

相鄰兄弟選擇器 (+)

<!DOCTYPE html>
<html>
<head>
<style>
div + p {
  background-color: yellow;
}
</style>
</head>
<body>

<h2>Adjacent Sibling Selector</h2>

<p>The + selector is used to select an element that is directly after another specific element.</p>
<p>The following example selects the first p element that are placed immediately after div elements:</p>

<div>
  <p>Paragraph 1 in the div.</p>
  <p>Paragraph 2 in the div.</p>
</div>

<p>Paragraph 3. After a div.</p>
<p>Paragraph 4. After a div.</p>

<div>
  <p>Paragraph 5 in the div.</p>
  <p>Paragraph 6 in the div.</p>
</div>

<p>Paragraph 7. After a div.</p>
<p>Paragraph 8. After a div.</p>

</body>
</html>

一般同級選擇器 (~)

<!DOCTYPE html>
<html>
<head>
<style>
div ~ p {
  background-color: yellow;
}
</style>
</head>
<body>

<h2>General Sibling Selector</h2>
<p>The general sibling selector (~) selects all elements that are siblings of a specified element.</p>

<p>Paragraph 1.</p>

<div>
  <p>Paragraph 2.</p>
</div>

<p>Paragraph 3.</p>
<code>Some code.</code>
<p>Paragraph 4.</p>

</body>
</html>

鏈接

link - 一個正常的，未訪問的鏈接 visited - 用戶訪問過的鏈接 hover - 用戶將鼠標懸停在其上時的鏈接 active - 點擊鏈接時的鏈接

<!DOCTYPE html>
<html>
<head>
<style>
/* unvisited link */
a:link {
  color: red;
}

/* visited link */
a:visited {
  color: green;
}

/* mouse over link */
a:hover {
  color: hotpink;
}

/* selected link */
a:active {
  color: blue;
}
</style>
</head>
<body>

<h2>CSS Links</h2>
<p><b><a href="default.asp" target="_blank">This is a link</a></b></p>
<p><b>Note:</b> a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective.</p>
<p><b>Note:</b> a:active MUST come after a:hover in the CSS definition in order to be effective.</p>

</body>
</html>

顯示 display

指定是否/如何顯示元素(指改變元素的顯示方式)

每個 HTML 元素都有一個默認顯示值，具體取決於它是什麼類型的元素。大多數元素的默認顯示值為blockor inline。

塊級元素

塊級元素總是從新行開始並佔據可用的整個寬度（盡可能向左和向右伸展）。


 - 




<形式>
<標題>
<頁腳>
<部分>


內聯元素

內聯元素不會從新行開始，只會佔用必要的寬度

元素類別

<跨度>

<圖片>

顯示:無 none

display: none;通常與 JavaScript 一起使用來隱藏和顯示元素，而無需刪除和重新創建它們

覆蓋默認顯示值

每個元素都有一個默認的顯示值。但是，可以覆蓋它。將內聯元素更改為塊元素，反之亦然。

<!DOCTYPE html>
<html>
<head>
<style>
li {
  display: inline;
}
</style>
</head>
<body>

<p>Display a list of links as a horizontal menu:</p>

<ul>
  <li><a href="/html/default.asp" target="_blank">HTML</a></li>
  <li><a href="/css/default.asp" target="_blank">CSS</a></li>
  <li><a href="/js/default.asp" target="_blank">JavaScript</a></li>
</ul>

</body>
</html>
資料來源:w3school