Leak detection and filling (I)

Math function

1. Math.abs()： Take the absolute value
2. Math.ceil()： Rounding up
3. Math.floor()： Rounding down
4. Math.round()： Round to the nearest whole
5. Math.random()： Get one [0,1) The random number
6. Math.min()： Get the minimum value in a set of numbers
7. Math.max()： Get the maximum value in a set of numbers
8. Math.PI： Get the pi π
9. Math.sqrt()： prescribing
10. Math.pow(x,y) ： Calculation x Of y Power

Common regular expressions

• Regular expression methods

1. str.match(regexp)： Retrieves the specified value within a string , Return the matching result as an array
2. str.search(regexp)： Retrieve the substring that meets the requirements within the string , And return the starting position of the substring in the string
3. str.repalce( Replaced regular requirements , replace content )： Replace the string required by the regular , Return the replaced string
4. regexp.test(str)： Check whether the string matches a pattern , If it's a return true, Not return false
5. regexp.exec(str)： Retrieves whether there is a match in the string , If there is a match, the matching result is returned , The result is an array type , No return null

console.log('xxxssss sss ffff'.match(/xxx/g)); //['xxx']
console.log('123ssss 123 sss f123fff'.match(/\./)); //null
console.log('1234ffff'.replace(/\d+/,5678)) //5678ffff
console.log('1234ffff'.search(/2/)) //1
console.log(/\d+/.exec('1234ffff1234')) //['1234', index: 0, input: '1234ffff1234', groups: undefined]
//exec Methods and match The method is very similar , but exec Methodical RegExp Objects do not have a global search （g） There is no later content 

• Common rules

7. \d：[0-9]
8. \w：[A-Za-z0-9] 、 Underline
9. \D： And \d contrary
10. \W： And \w contrary
11. \s： Space
12. \S： And \s contrary
13. +： Match the previous expression 1 Times or times
14. *： Match the previous expression 0 Times or times
15. {n,}： At least n Time
16. {n, m}：n To m Time

more ：https://www.cnblogs.com/lnlvinso/p/10467941.html

marquee label

Be careful ：marquee Labels have been eliminated
direction attribute ：left（ From right to left ）、right（ From left to right ）、up、down
scrolldelay attribute ： Time interval of each scroll

CSS Animation

1. keyframe The rules

@keyframe name{
  from/0%{ Corresponding css style }
  25%{ Corresponding css style }
  50%{ Corresponding css style }
  75%{ Corresponding css style }
  to/100%{ Corresponding css style }
}

2. animation attribute

animation-delay： Animation execution delay time 
animation-duration：  Duration of animation completion 
animation-direction： The execution direction of animation （normal、alternate）
animation-name： The name of the execution animation 
animation-iteration-count：  The number of times the animation is executed 
animation-timing-function： The speed at which the animation is executed 
animation-fill-code： The style when the animation is not played （none、forwards、backwards、both）
animation-play-state： Set the animation to pause or execute （paused、running）

Shorthand order ：animation-name animation-duration animation-timing-funciton animation-iteration-count animation-direction

JS All the data in the are based on 64 Bit floating point data (float) To store . Basic type variables are used 8 Byte memory ：8byte=64bit

Inheritable CSS attribute

1. font Series properties 
2. text-indent： Indent text 
3. text-align： Align text horizontally 
4. line-height： Row height 
5. word-spacing： Increase or decrease the space between words （ I.e. word spacing ）
6. letter-spacing： Increase or decrease the space between characters （ Between characters ）
7. text-transform： Control text case 
8. direction： Set the writing direction of the text 
9. color： text color 
10. visibility： Whether elements are visible 

https://www.cnblogs.com/thislbq/p/5882105.html

audio And video

audio label 、audio Object methods

attribute ：

1. autoplay： If the attribute appears , The audio will play as soon as it is ready
2. controls： If the attribute appears , The control is displayed to the user , For example, play button
3. loop： If the attribute appears , Then it starts playing again every time the audio ends
4. muted： Specifies that the video output should be muted
5. preload ： If the attribute appears , Then the audio is loaded when the page is loaded , And get ready to play
6. src： Of the audio to be played URL

Object methods ：

1. load()： load
2. play()： Play
3. pause()： Pause
4. canPlayType()： Check whether the browser can play the specified type of audio
5. addTextTrack()： Add a new text track to the audio
6. fastSeek()： Specify the playback time

event ：
abort： Triggered when the download is terminated
ended： Trigger when playback is complete
seeked： User mobile 、 Trigger when jumping to a new position

video label 、video Object methods

attribute ：
stay audio Add... On the basis of the label 3 Attributes

1. width： Width
2. height： Height
3. post： Specify the image to be displayed when the video is downloaded , Or the image displayed before the user clicks the play button

Object methods ：
And audio Object methods are consistent

table label

<table border="1">
  <tr>
    <th>xxxxx</th>
    <th>yyyyy</th>
  </tr>
  <tr>
    <td>kkkkk</td>
    <td>wwwww</td>
  </tr>
</table>

table Confusing properties ：
1. cellpadding： The distance between the text in the table and the border 
2. cellspacing： Distance between cells 

SVG And canvas The difference between

1. SVG The elements drawn are independent DOM node ,canvas What is drawn is a whole canvas , therefore canvas Produced DOM Quantity ratio SVG Less
2. SVG have access to css Set animation styles ,canvas Can not be

canvas label

// Open up a canvas Space 
<canvas id="myCanvas"></canvas>
<script>
// Find this space and get drawing tools for it 
var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext('2d');
// Use canvas Tools for drawing 
...
</script>

https://blog.csdn.net/ff906317011/article/details/80415137

menu label

// Define menu list . Use this tag when you want to list form controls 
<menu label="File">
	<li></li>
	<li></li>
	<li></li>
</menu>
<menu label="Edit">
	<li></li>
	<li></li>
	<li></li>
</menu>

command label

// Label definition command button , For example, radio buttons 、 Check boxes or buttons 
// Only in menu The label defines command The label will be displayed , At present, only IE Support command label 
<menu>
	<command onclick="alert('click')"> Click on </command>
</menu>

Main attributes ：
type：checkbox、command（ Default ）、radio
checked： Defines whether it is selected . Only used for radio or checkbox type
disabled： Definition command Is it available
radiogroup： Definition command The name of the group to which it belongs . Only if the type is radio When using .