Markdown is a way to write web content. Formatting text in Markdown doesn’t do anything fancy like changing font size, color, or type in CSS, instead it only defines different formatting elements through putting a few symbols, such as asterisks(*) and backticks(), around plaintext to display the plaintext as bold, headers, lists, code blocks, etc. Technically speaking, Markdown is simplier than HTML and CSS to format your web content. This is one of the reasons why I moved my blog from Wordpress.com to Github Pages. In this post I listed out some frequently used formatting elements syntax in Markdown. It have been used as a quick reference for my daily writing.

## 1. Block Elements

### 1.1 Paragraphs and Breaks

Paragraphs consist of one or more consecutive lines of text that are separated by one or more blank lines. If a line contains only spaces, it is a blank line. Blocks of text separated by one or more blank lines will be parsed as paragraphs. If you want to create a line break, simply end a line with two or more spaces, then hit Return/Enter.

Headers work as titles and subtiles for sections. To create a header, simply prefix your header text with the number of hash marks (#) to specify heading depth. For example: # Header 1, ## Header 2 and ### Header 3 will be progressively smaller headers. You can end your headers with any number of hashes.

### 1.3 Blockquotes

A blockquote is a sentence or paragraph from another source that’s been specially formatted to draw attention to the reader. To create a block quote, all you have to do is preface a line or a paragraph with the “greater than” caret (‘>’). For example:

> "In a few moments he was barefoot, his stockings folded in his pockets and his
canvas shoes dangling by their knotted laces over his shoulders and, picking a
pointed salt-eaten stick out of the jetsam among the rocks, he clambered down
the slope of the breakwater."


would generate a blockquote as:

“In a few moments he was barefoot, his stockings folded in his pockets and his canvas shoes dangling by their knotted laces over his shoulders and, picking a pointed salt-eaten stick out of the jetsam among the rocks, he clambered down the slope of the breakwater.”

Note: if you decide to hard-wrap text, you need to prefix each line of your quote with a > character.

### 1.4 Lists

Markdown supports both ordered and unordered lists. To create an ordered list, simply prefix each line with a number and a dot .. To create an unordered list, you can prefix each line with one of the characters *, + or -. One list item can contain multiple paragraphs, however each paragraph must be indented by at least 4 spaces or a tab. For example:

1. Fruit:
* Pears
* Peaches
* Apples
+ Granny Smith
+ Gala
* Oranges
* Bananas
2. Dairy:
- Milk
+ Whole
+ Skim


will be interpreted as:

1. Fruit:
• Pears
• Peaches
• Apples
• Granny Smith
• Gala
• Oranges
• Bananas
2. Dairy:
• Milk
• Whole
• Skim

### 1.5 Code Blocks

Code can either in the middle of a paragraph (Inline Code), or as a block. To include a complete code-block, you can use triple backquotes. Optionally, you can put the name of the language that you are quoting after the starting triple backticks, like this:

python
def plusOne(n):
return n + 1



That will format the code-block (sometimes called “fenced code”) with syntax coloring. The above code block would be rendered like:

def plusOne(n):
return n + 1


### 1.6 Section Blocks

Sections can be separated by horizontal rules, which are created by placing three or more hyphens(‘-‘), underscores(‘ _ ‘) or asterisks(‘ * ‘) on a line by themselves, for example:

---
___

***


will create three horizontal rules:

## 2 Span Elements

### 2.1 Style and Emphsis

In most of browsers, text surrounded with asterisks ( * ) or underscores ( _ ) are displayed as italics, while text surrounded by double asterisks ( ** ) or double underscores ( __ ) are rendered as bold.

Note: There is no space between the starting asterisks and the text.

### 2.2 Inline Code

You can use a single backtick () to start and stop code in the middle of a paragraph. Here’s an example:

The word function will appear in a code-like form.


The word function will appear in a code-like form.

If you want to include a literal backtick in your code, you can suround the whole text block in double backticks like this:

Look at this literal  backtick 


Look at this literal backtick

Automatic link is a link that displays the actual URL. To make an automatic link, you can surround the URL with < >. For example,

<http://github.com/>


would dispaly the URL of GitHub: http://github.com/

A standard link can be created through putting the text to display in a pair of brackets ([]) and the URL within parentheses. In the parentheses you can also specify the mouse-over title with double quotes.

[Click to GitHub](http://github.com/ "GitHub")


Relative paths are allowed in link parentheses, for example:

[Click to Table of Content](#table-of-content)


Click to Table of Content

Instead of putting the URL immediately after a brackets, you can put a reference tag in a bracket after it and link the URL to the reference tag later on. For example,

[Click to GitHub][ref to github]
...
[ref to github]:http://github.com/ "GitHub"


Click to GitHub

### 2.4 Images

Markdown image syntax is almost the seame syntax for links. You just need to put an exclamation point (!) before the first set of brackets. For example,

![whatever you write here](http://github.com/unicorn.png "picture of unicorn")


You can also make a reference-style, for example,

![][unicorn]
[unicorn]:http://github.com/unicorn.png


### 2.5 Backslash Escape

To show a literal character, like a *, that has a specific function in Markdown, you can put a backslash (\) before the character. For example,

\* This is not a bullet

* This is a bullet


* This is not a bullet

• This is a bullet

Markdown allows you to use a backslash to escape from the functions of the following characters:

• \ backslash
•  backtick
• * asterisk
• _ underscore
• {} curly braces
• [] square brackets
• () parentheses
• # hashtag
• + plus sign
• - minus sign (hyphen)
• . dot
• ! exclamation mark

## 3. Tables

In Markdown, you can make a table by using vertical bars and dashes to define the cell and header borders:

|Header|Header|Header|Header|
|------|------|------|------|
|Cell  |Cell  |Cell  | Cell |
|Cell  |Cell  |Cell  | Cell |
|Cell  |Cell  |Cell  | Cell |
|Cell  |Cell  |Cell  | Cell |

Cell Cell Cell Cell
Cell Cell Cell Cell
Cell Cell Cell Cell
Cell Cell Cell Cell

You don’t need to include all of those dashes, vertical bars, and spaces for Markdown to understand that you’re making a table. Here’s the bare minimum you would need to create the table above:

Header|Header|Header|Header
-|-|-|-
Cell|Cell|Cell|Cell
Cell|Cell|Cell|Cell
Cell|Cell|Cell|Cell
Cell|Cell|Cell|Cell

Cell Cell Cell Cell
Cell Cell Cell Cell
Cell Cell Cell Cell
Cell Cell Cell Cell

You can also specify either header justification or centering, for example,

centered header  |  regular header  |  right-justified header
:-:|-|-:
centered cell|regular cell|right-justified cell
centered cell|regular cell|right-justified cell

centered cell regular cell right-justified cell
centered cell regular cell right-justified cell

Note: You cannot make tables directly beneath a line of text. You must put a blank line between the end of a paragraph and the beginning of a table.

## 4. Math Equations

If your Markdown supports MathJax, you can write math equaiton. For example,

$$x^2 + y^2 = z^2$$

will display a block of equation:

$x^2 + y^2 = z^2$
\$x^2 + y^2 = z^2 \$

is another way to build a bock equation:

$x^2 + y^2 = z^2$

\$$x^2 + y^2 = z^2 \$$`

will show an inline function $$x^2 + y^2 = z^2$$.