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In this article Xiaobian for you to introduce in detail the "html5 string regular judgment and matching methods", the content is detailed, the steps are clear, the details are handled properly, I hope this "html5 string regular judgment and matching methods" article can help you solve your doubts, the following follow the editor's ideas slowly in-depth, together to learn new knowledge.

How to determine that the incoming string contains a closed html tag

/ / i

In fact, this can not determine the integrity or order of tag closure, but whether there are html tags (including custom tags) in the string, which is enough for me. What you need to learn in the rule is that [sS] can represent all strings.

/. * / I

This is more standardized and can match a fully closed tag. 1 represents the content captured in the previous parentheses, which is a more advanced use of regular.

How to match the text content in a tag

Str = str.replace (/ [sS] *? /,''+ newTitle +'')

It's best to match with a semantic tag or a custom tag. If you use div, there may be many in a string, and there will be many problems.

[sS] * stands for any character

* in the back? Represents non-greedy mode, because regular matching defaults to greedy mode

Summary

Using regular matching text from html tags is actually a very inefficient way, and there is no need to use it when it is not necessary. There is an article that deeply criticizes this behavior and is interested to take a look at it.

Common regular expressions

Regular expression that matches Chinese characters: [u4e00-u9fa5]

Note: matching Chinese is really a headache. It's easy to have this expression.

Match double-byte characters (including Chinese characters): [^ x00-xff]

Note: can be used to calculate the length of a string (a double-byte character length meter 2 ~ ~ ASCII character counter 1)

A regular expression that matches a blank line: ns*r

Comment: can be used to delete blank lines

Regular expression that matches the HTML tag:] * >. *? |

Commentary: the version circulated on the Internet is too bad, the above one can only match part of it, and there is still nothing I can do about complex nested tags.

Regular expression that matches the leading and trailing white space characters: ^ s* | slots $

Comment: a very useful expression that can be used to delete white space characters (including spaces, tabs, page feeds, etc.) at the beginning and end of a line

Regular expression that matches the Email address: W + ([- +.] w +) * @ w + ([-.] w +) * .w + ([-.] w +) *

Comment: form validation is very useful

The regular expression that matches the URL URL: ^ (http | https): / / [wmurf _] + (. [wmurf _] +) + ([wmur.dome? ^ =% &: / ~ + #] * [wMI? ^ =% & / ~ + #])?

Note: the function of the version circulated on the Internet is very limited, and the above version can basically meet the needs.

Whether the matching account is legal (5-16 bytes are allowed at the beginning of the letter, and alphanumeric underscores are allowed): ^ [a-zA-Z] [a-zA-Z0-9 _] {4j 15} $

Comment: form validation is very useful

Match domestic phone number: d {3}-d {8} | d {4}-d {7}

Commentary: matching forms such as 0511-4405222 or 021-87888822

Match Tencent QQ number: [1-9] [0-9] {4,}

Commentary: Tencent QQ starts from 10000

Match the postcode of China: [1-9] d {5} (?! d)

Commentary: the postal code of China is 6 digits

Match ID: d {15} | d {18}

Commentary: Chinese ID cards are 15 or 18 digits

Match the ip address: dong.dharm.ding.d+

Note: useful when extracting ip addresses

Match specific numbers:

^ [1-9] $/ / match positive integers

^-[1-9] $/ / match negative integers

^ -? [1-9] d _ match $/ / match integer

^ [1-9] d * | 0 $/ / matches a non-negative integer (positive integer + 0)

^-[1-9] d * | 0 $/ / matches non-positive integers (negative integers + 0)

^ [1-9] dquo.d* | 0.d* [1-9] droom$ / / matches positive floating point numbers

^-([1-9] dfol.d* | 0.d* [1-9] d*) $/ / matches negative floating point numbers

^ -? ([1-9] droom.d* | 0.d* [1-9] d* | 0room.0+ | 0) $/ / match floating point number

^ [1-9] dfol.d* | 0.d* [1-9] d* | 0room.0+ | 0 $/ / match non-negative floating point number (positive floating point number + 0)

^ (- ([1-9] dfu.d* | 0.d* [1-9] d*)) | 0room.0+ | 0 $/ / matches non-positive floating point numbers (negative floating point numbers + 0)

Commentary: useful when dealing with a large amount of data, pay attention to corrections in specific applications

Match a specific string:

^ [A-Za-z] + $/ / matches a string of 26 English letters

^ [Amurz] + $/ / matches a string of 26 English letters in uppercase

^ [amurz] + $/ / matches a string of 26 lowercase letters

^ [A-Za-z0-9] + $/ / matches a string of numbers and 26 letters

^ wrist $/ / matches a string consisting of numbers, 26 letters, or underscores

The validation features and their validation expressions when using RegularExpressionValidator validation controls are described as follows:

You can only enter a number: "^ [0-9] * $"

Only n-digit numbers can be entered: "^ d {n} $"

You can only enter at least n digits: "^ d {n,} $"

You can only enter the number of mmurn digits: "^ d {mdirection n} $"

You can only enter zero and non-zero numbers: "^ (0 | [1-9] [0-9] *) $"

You can only enter positive real numbers with two decimal places: "^ [0-9] + (. [0-9] {2})? $"

You can only enter positive real numbers with 1-3 decimal places: "^ [0-9] + (. [0-9] {1pr 3})? $"

You can only enter a positive integer that is not zero: "^ +? [1-9] [0-9] * $"

You can only enter a negative integer that is not zero: "^-[1-9] [0-9] * $"

Only characters of length 3 can be entered: "^. {3} $"

You can only enter a string of 26 letters: "^ [A-Za-z] + $"

You can only enter a string of 26 capital letters: "^ [Amurz] + $"

You can only enter a string of 26 lowercase letters: "^ [amurz] + $"

You can only enter a string of numbers and 26 letters: "^ [A-Za-z0-9] + $"

You can only enter a string consisting of numbers, 26 letters, or an underscore: "^ wicked $"

Verify the user password: "^ [a-zA-Z] w {5pm 17} $" is in the correct format: begins with a letter, is between 6 and 18 in length, and can only contain characters, numbers, and underscores.

Verify that it contains characters such as ^% &',; =? $":" [^% &',; =? $x22] + "

You can only enter Chinese characters: "^ [u4e00-u9fa5], {0,} $"

Verify the Email address: "^ w + [- +.] w +) * @ w + ([-.] w +) * .w + ([-.] w +) * $"

Verify the phone number: "^ ((d {3pr 4}) | d {3pr 4} -)? d {7pr 8} $"

The correct format is "XXXX-XXXXXXX", "XXXX-XXXXXXXX", "XXX-XXXXXXX"

"XXX-XXXXXXXX", "XXXXXXX", "XXXXXXXX".

Verify ID number (15 or 18 digits): "^ d {15} | d {} 18 $"

Verify the 12 months of the year: "^ (0? [1-9] | 1 [0-2]) $" the correct format is: "01"-"09" and "1"12"

Verify 31 days of a month: "^ ((0? [1-9]) | (1 | 2) [0-9]) | 30 | 31) $"

The correct formats are "01", "09" and "1"31".

Regular expression that matches Chinese characters: [u4e00-u9fa5]

Match double-byte characters (including Chinese characters): [^ x00-xff]

Regular expression that matches blank lines: n [s |] * r

Regular expression that matches the HTML tag: /. * | /

Regular expression that matches leading and trailing spaces: (^ s*) | (sworn $)

After reading this, the article "methods for regular judgment and matching of html5 strings" has been introduced. If you want to master the knowledge points of this article, you still need to practice and use it yourself to understand it. If you want to know more about related articles, please follow the industry information channel.

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