Form validation Common (strongly recommended favorites) _ Regular expressions

1. ^\d+$//matching nonnegative integer (positive integer + 0)
2. ^[0-9]*[1-9][0-9]*$//Matching positive integer
3. ^ ((-\d+) | (0+)) $//matching non positive integer (negative integer + 0)
4. ^-[0-9]*[1-9][0-9]*$//matching negative integers
5. ^-?\d+$//Matching integer
6. ^\d+ (\.\d+)? $//matching nonnegative floating-point number (positive floating-point number + 0)
7. ^ ([0-9]+\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\. [0-9]+) | ([0-9]*[1-9][0-9]*)] $//matching positive floating-point numbers
8. ^ ((-\d+ (\.\d+)?) | (0+ (\.0+)) $//matching non-positive floating-point numbers (negative floating-point number + 0)
9. ^ (-([0-9]+\. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\. [0-9]+) | ([0-9]*[1-9][0-9]*))] $///Match negative floating-point number
10. ^ (-?\d+) (\.\d+)? $//matching floating-point number
11. ^[a-za-z]+$//Match a string of 26 English letters
12. ^[a-z]+$//Match a string of 26 uppercase letters
13. ^[a-z]+$//Match string consisting of 26 lowercase letters
14. ^[a-za-z0-9]+$//Match a string of numbers and 26 English letters
15. ^\w+$//Match A string of numbers, 26 English letters, or underscores
16. ^[\w-]+ (\.[ \w-]+) *@[\w-]+ (\.[ \w-]+) +$//matching email address
17. ^[a-za-z]+://Match (\w+ (-\w+) *) (\. ( \w+ (-\w+) *) * (\?\s*)? $//matching URL
18. Matching regular expressions for Chinese characters: [\U4E00-\U9FA5]
19. Match Double-byte characters (including Chinese characters): [^\x00-\xff]
20. Application: Computes the length of the string (a double-byte character length meter 2,ascii character 1)
String.prototype.len=function () {return This.replace ([^\x00-\xff]/g, "AA"). Length;}
21st. A regular expression that matches a blank row: \n[\s|] *\r
22. Regular expression matching HTML tags:/< (. *) >.*<\/\1>|< (. *) \/>/
23. Matching a regular expression with a trailing space: (^\s*) | (\s*$)

* Regular expression Use cases
* 1, ^\s+[a-z a-z]$ can not be empty can not be a space can only be English letters
* 2, \s{6, can not be empty for more than six digits
* 3, ^\d+$ can not have a space can not be not a digital
* 4, (. *) (\.jpg|\.bmp) $ can only be JPG and BMP format
* 5, ^\d{4}\-\d{1,2}-\d{1,2}$ can only be 2004-10-22 format
* 6, ^0$ at least one of the selected
* 7, ^0{2,}$ select at least two
* 8, ^[\s|\s]{20,}$ can not be empty for more than 20 words
* 9, ^\+? [A-z0-9] (([-+.]| [_]+)? [a-z0-9]+) *@ ([A-z0-9]+ (\.| \-)) +[a-z]{2,6}$ Mail
* 10, \w+ ([-+.] \w+) *@\w+ ([-.] \w+) *\.\w+ ([-.] \w+) * ([,;] \s*\w+ ([-+.] \w+) *@\w+ ([-.] \w+) *\.\w+ ([-.] \w+) *) * Enter multiple addresses separate messages with commas or spaces
* 11, ^ ([0-9]+\)]? [0-9] {7,8}$ Phone number 7-bit or 8-bit or preceded by an area code such as (022) 87341628
* 12, ^[a-z-Z 0-9 _]+@[a-z-z 0-9 _]+ (\.[ A-Z 0-9 _]+) + (\,[a-z-Z 0-9 _]+@[a-z-z 0-9 _]+ (\.[ A-Z 0-9 _]+) + *$
* Can only be letters, numbers, underscores; must have @ and. Simultaneous format to standardize messages
* ^\w+@\w+ (\.\w+) + (\,\w+@\w+ (\.\w+) +) *$ The above expression can also be written in this way, more concise.
^\w+ ((-\w+) | ( \.\w+)) *\@\w+ (\.| -) *\.\w+$ [/size] \w+)

Matching regular expressions for Chinese characters: [\U4E00-\U9FA5]
Commentary: Matching Chinese is really a headache, with this expression will be easy to do

Match Double-byte characters (including Chinese characters): [^\x00-\xff]
Commentary: can be used to compute the length of a string (a double-byte character length meter 2,ascii 1 characters)

A regular expression that matches a blank row: \n\s*\r
Commentary: can be used to delete blank lines

Regular expressions that match HTML tags: < (\s*?) [^>]*>.*?| <.*? />
Commentary: The online version is too bad, the above can only match the part of the complex nested tags still powerless

A regular expression that matches the end-end whitespace character: ^\s*|\s*$
Commentary: A useful expression that can be used to delete white-space characters (including spaces, tabs, page breaks, and so on) at the end of a line at the beginning

Regular expression matching an email address: \w+ ([-+.] \w+) *@\w+ ([-.] \w+) *\.\w+ ([-.] \w+) *
Commentary: Form validation is useful

Regular expressions that match URL URLs: [a-za-z]+://[^\s]*
Commentary: Online circulation of the version of the function is very limited, which can meet the basic requirements

Match account number is legal (beginning of letter, allow 5-16 bytes, allow alphanumeric underline): ^[a-za-z][a-za-z0-9_]{4,15}$
Commentary: Form validation is useful

Match domestic phone number: \d{3}-\d{8}|\d{4}-\d{7}
Commentary: Match form such as 0511-4405222 or 021-87888822

Matching Tencent QQ Number: [1-9][0-9]{4,}
Commentary: Tencent QQ number starting from 10000

Match China ZIP Code: [1-9]\d{5} (?! \d)
Commentary: China postal code is 6 digits

Matching ID: \d{15}|\d{18}
Commentary: China's ID card is 15-or 18-digit

Matching IP address: \d+\.\d+\.\d+\.\d+
Commentary: Useful when extracting IP addresses

Match a specific number:
^[1-9]\d*$//Matching positive integer
^-[1-9]\d*$//matching negative integers
^-? [1-9]\d*$//matching integer
^[1-9]\d*|0$//matching nonnegative integer (positive integer + 0)
^-[1-9]\d*|0$//matching non positive integer (negative integer + 0)
^[1-9]\d*\.\d*|0\.\d*[1-9]\d*$//matching positive floating-point numbers
^-([1-9]\d*\.\d*|0\.\d*[1-9]\d*) $//matching negative floating-point number
^-? ([1-9]\d*\.\d*|0\.\d*[1-9]\d*|0?\.0+|0) $//matching floating-point number
^[1-9]\d*\.\d*|0\.\d*[1-9]\d*|0?\.0+|0$//matching nonnegative floating-point number (positive floating-point number + 0)
^ (-([1-9]\d*\.\d*|0\.\d*[1-9]\d*)) |0?\.0+|0$//matching non-positive floating-point numbers (negative floating-point number + 0)
Commentary: useful when dealing with large amounts of data, pay attention to corrections when applied

Match a specific string:
^[a-za-z]+$//Match a string of 26 English letters
^[a-z]+$//Match a string of 26 uppercase letters
^[a-z]+$//Match string consisting of 26 lowercase letters
^[a-za-z0-9]+$//Match a string of numbers and 26 English letters
^\w+$//Match A string of numbers, 26 English letters, or underscores

Regular several basic concepts:

1. Greed: +,*,?, {m,n}, etc. default is greedy match, that is, as many matches as possible, also called the maximum match
If the following is added, it is converted to a non greedy match and requires a high version of support

2. Get: By default (X|y) is to get matching, many times just testing, not necessarily required to get the matching data, especially in the nested matching or large data to be used to match (?: X|y), so as to improve efficiency, optimize the program.

3. Consumption: The default is the consumption of matching, generally in the preliminary search is not consumption matching.
For example, 2003-2-8 will become 2003-02-08.
If use/-(\d)-/second match will start from 8, thereby replacing only the first 2, the error
If you use/-(\d) (? =-)/Then the second match starts with the second--no characters are consumed

4. Pre-check: JS is divided into forward check and negative pre-check
As the above (? =pattern) is forward lookup, match the find string at the beginning of any string matching pattern. and (?!) pattern) is a negative lookup that matches the search string at the beginning of any string that does not match the pattern. Negative pre-check is sometimes used in the expansion of [^], [^] just some characters, and?! Can make the entire string.
5. Callback: Generally used in the replacement, that is, based on the use of matching content to return unused replacement value, thereby simplifying the program, the need for a high version of support

6. Reference: \num a reference to the obtained Num.
For example, ' (.) \1\1 ' matches AAA type. '(.) (.) \2\1 ' Match ABBA type.

Regular expression reserved word
^ (carat)
. (period)
[(Left Bracket}
$ (dollar sign)
((left parenthesis)
) (right parenthesis)
| (pipe)
* (asterisk)
+ (plus symbol)
? (question mark)
{(left curly bracket, or left brace)
\ Backslash

Regular expression reserved word
^ (carat)
. (period)
[(Left Bracket}
$ (dollar sign)
((left parenthesis)
) (right parenthesis)
| (pipe)
* (asterisk)
+ (plus symbol)
? (question mark)
{(left curly bracket, or left brace)
\ backslash View plaincopy to Clipboardprint?
Constructs match the

Construct match view Plaincopy to Clipboardprint?
Character
X character X
\ backslash Character
\0n octal value of the character 0n (0 <= n <= 7)
\0nn octal value of the character 0nn (0 <= n <= 7)
\0mnn octal value of characters 0mnn 0mnn (0 <= m <= 3, 0 <= n <= 7)
\XHH hexadecimal-value character 0xhh
\uhhhh hexadecimal-value character 0xhhhh
\ t tab (' \u0009 ')
\ n line feed (' \u000a ')
\ r return character (' \u000d ')
\f page feed (' \u000c ')
\a Bell character (' \u0007 ')
\e Escape character (' \u001b ')
\CX t corresponds to X's control character X

Character
X character X
\ backslash Character
\0n octal value of the character 0n (0 <= n <= 7)
\0nn octal value of the character 0nn (0 <= n <= 7)
\0mnn octal value of characters 0mnn 0mnn (0 <= m <= 3, 0 <= n <= 7)
\XHH hexadecimal-value character 0xhh
\uhhhh hexadecimal-value character 0xhhhh
\ t tab (' \u0009 ')
\ n line feed (' \u000a ')
\ r return character (' \u000d ')
\f page feed (' \u000c ')
\a Bell character (' \u0007 ')
\e Escape character (' \u001b ')
\CX t corresponds to X's control character x view Plaincopy to Clipboardprint?
Character class
[ABC] A, B, or C (simple Class)
[^ABC] Any character other than a, B, or C (negation)
[A-za-z] A to Z or A to Z, inclusive (range)
[A-Z-[BC]] A to Z, except B and C: [Ad-z] (minus)
[A-z-[m-p]] A to Z, except m to P: [A-lq-z]
[A-z-[^def]] D, E, or F

Character class
[ABC] A, B, or C (simple Class)
[^ABC] Any character other than a, B, or C (negation)
[A-za-z] A to Z or A to Z, inclusive (range)
[A-Z-[BC]] A to Z, except B and C: [Ad-z] (minus)
[A-z-[m-p]] A to Z, except m to P: [A-lq-z]
[A-z-[^def]] D, E, or F view plaincopy to Clipboardprint?
Predefined character classes
. Any character (may be able to match the line terminator, maybe not)
\d number: [0-9]
\d Non-digit: [^0-9]
\s spaces: [\t\n\x0b\f\r]
\s Non spaces: [^\s]
\w Word characters: [a-za-z_0-9]
\w non-word characters: [^\w]