Basic front-end knowledge accumulation

1,

Before the tag.
In HTML 4.01, HTML5 is not based on SGML, so you do not need to reference DTD.
Tip: please always add to HTML document

2. What are in-row and block-level elements? (You can refer to the link below for comprehensive answers)
Http://blog.sina.com.cn/s/blog_72c8c1150100q76q.html

Excerpt accumulation:
Remember the Line Element
The width setting is invalid.
The height setting is invalid. You can use line-height to set the height.
Only the left and right margin values are valid when you set margin.
When padding is set, only the left and right padding are valid, and the up and down are invalid. Note that the element range is increased, but it does not affect the content around the element. You can see the effect on the image.

The text-align attribute is different between the two.

3. This process of writing different CSS codes for different browsers is called CSS hack!
IE8 latest CSS hack:
"\ 9" Example: "border: 1px \ 9;". Here "\ 9" can distinguish all IE and Firefox. (Only for ie9 hack)
"\ 0" IE8 identification, IE6, IE7 cannot.
"*" IE6 and IE7 can be identified. IE8 and Firefox cannot.
""IE6 can recognize"", IE7, IE8, Firefox cannot.

Baidu encyclopedia inside the description is very clear: http://baike.baidu.com/view/1119452.htm

4. CSS Cascade
(1), weight (2), inheritance

Author Style
The author can determine an external and independent CSS file in his html file.
The author can include CSS information in HTML files.
The author can combine CSS commands in an HTML command to offset the overall CSS command in a special case.

Reader style
Readers can create a regional CSS file in their browsers. This CSS file can be used on all HTML files. If the author's CSS file conflicts with the reader, the reader can determine which one he wants to use

Browser style
If a style is not specified externally, the browser generally has an internal style.

The above are some answers. The descriptions in w3cshool are:
Cascade order
Which style will be used when the same HTML element is defined by more than one style?
Generally, all styles are stacked in a new virtual style table according to the following rules, where number 4 has the highest priority.
1. default browser settings
2. External Style Sheets
3. Internal style sheet (inside the label)
4. inline style (inside the HTML element)

Take the time to write an example to test the differences between these tags.

5,
What are position values and what are new content in css3.

6. Understand the browser kernel:
The most important or core part of a browser is "rendering engine", which can be roughly translated as "Interpretation engine", but we generally call it "browser kernel ". Responsible for interpreting webpage syntaxes (such as HTML and JavaScript) and rendering (displaying) webpages. Therefore, the so-called browser kernel is the rendering engine used by the browser. The rendering engine determines how the browser displays webpage content and page format information. Different browser kernels have different interpretations of the webpage syntax, so the rendering (Display) Effects of the same webpage in browsers of different kernels may also be different, this is why Web page writers need to test the web page display effect in browsers with different kernels. There are a lot of browser kernels. If almost no one is using a non-commercial free kernel, there may be more than 10 or more, however, there are usually only four of them.

7. Regular Expression:
[1] [358] [0-9] {9} $ telephone number matching
[\ W-] + (. [\ W-] +) * @ [\ W-] + (. [\ W-] +) + $ email matching (not verified yet, just a reference answer is found, and it will take time to verify)

8. Cookie basics:

The cookie object attributes are as follows:
1. Name: Get or set the cookie name.
2. Value: Get or set the cookie value.
3. expires: Get or set the cookie expiration date and event.
4. Version: Get or set the version that meets the HTTP maintenance status of the cookie.

The cookie object method is as follows:
1. Add: Add cookie variable.
2. Clear: Clear the variables in the cookie set.
3. Get: get the cookie variable value through the variable name or index.
4. Remove: delete a cookie object by using the cookie variable name or index.

9. node operations: http://blog.sina.com.cn/s/blog_a564ddcd0101dws9.html
This blog is very detailed. For details, refer.

10. Sizzle is a pure JavaScript CSS selector engine. (Take A Look At the source code http://www.oschina.net/p/sizzle)
Sizzle is a pure JavaScript CSS selector engine.
Generally, the matching mode of selector (including before jq1.2) is an ordered way of thinking. When you need to perform a progressive match, such as $ ('div size, all the operations performed are to match the DIV in the page first and then match the span tag under its node, and then return the result.
Sizzle adopts the opposite right-to-left implementation method. It first searches for all span labels on the page and then determines its parent node (including parent nodes and above) in the subsequent operations) if it is a DIV, It is pushed into the array. Otherwise, pass enters the next judgment and returns the operation sequence.

11. Basic knowledge about Javascript:
(1) What are the status messages of the HTTP protocol? (For example, descriptions of 200 and 302)

(2) What is Ajax? Ajax interaction model (process )? What is the cross-origin Ajax solution?
What Is Ajax?
Ajax = Asynchronous JavaScript and XML (Asynchronous JavaScript and XML ).
Ajax is not a new programming language, but a new method that uses existing standards.
Ajax is the art of exchanging data with the server and updating some webpages without reloading the entire page.

(What is the process) Reference answer (you can try it ):

1 -- start to get XMLHTTPRequest object 2 -- open to open the URL channel and set asynchronous transmission 3 -- send to send data to server 4 -- the Server accepts and processes the data, result 5 returned after processing is complete -- the client receives the result from the server.

It should be able to determine the status

The cross-origin solution cannot be understood yet, because the most basic solution is not familiar yet.

(3) What is the difference between synchronization and Asynchronization?

Basic front-end knowledge accumulation