Accumulate regular expressions that are more commonly used (for example, matching Chinese, matching html) _ Regular expressions

Regular Expressions (Regular Expression, often abbreviated as regex, RegExp, or re) in code are a concept of computer science. A regular expression uses a single string to describe and match a series of strings that conform to a certain syntactic rule. In many text editors, regular expressions are often used to retrieve and replace text that conforms to a pattern. Many programming languages support the use of regular expressions for string manipulation. In many text editors, regular expressions are often used to retrieve and replace text that conforms to a pattern.

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: ns*r
Commentary: can be used to delete blank lines
Regular expression:< matching 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$//matching non-positive floating-point numbers (negative floating-point number + 0)
Commentary: useful when dealing with large amounts of data, pay attention to corrections when applied
Match a specific string:
^[a-za-z]+$//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
The validation features and their validation expressions when using the RegularExpressionValidator validation control are described below:
Only numbers can be entered: "^[0-9]*$"
Only n digits can be entered: "^d{n}$"
You can enter at least n digits: "^d{n,}$"
Only m-n digits can be entered: "^d{m,n}$"
Only numbers beginning with 0 and not 0 can be entered: ^ (0|[ 1-9][0-9]*) $ "
You can only enter positive real numbers with two decimal digits: ^[0-9]+ (. [ 0-9]{2})? $ "
You can only enter positive real numbers with 1-3 decimal digits: ^[0-9]+ (. [ 0-9]{1,3})? $ "
You can only enter a Non-zero positive integer: "^+?" [1-9] [0-9]*$]
You can only enter a Non-zero negative integer: "^-[1-9][0-9]*$"
You can only enter characters with a length of 3: "^. {3}$ "
You can only enter a string of 26 English letters: "^[a-za-z]+$"
You can only enter a string of 26 uppercase English letters: "^[a-z]+$"
You can only enter a string consisting of 26 lowercase English letters: "^[a-z]+$"
You can only enter a string of numbers and 26 English letters: "^[a-za-z0-9]+$"
You can only enter a string of numbers, 26 English letters, or underscores: "^w+$"
Verify user password: "^[a-za-z]w{5,17}$" in the correct format: Beginning with the letter, length between 6-18,
Only characters, numbers, and underscores can be included.
Verify that there are ^%& ',; =?$ ' characters: "[^%&",; = $x 22]+ "
Only Chinese characters can be entered: "^[u4e00-u9fa5],{0,}$"
Verify email Address: "^w+[-+." w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *$ "
Verify InternetURL: "^http://([w-]+.) +[w-]+ (/[w-./?%&=]*)? $ "
Verify phone Number: "^ ((d{3,4}) |d{3,4}-)? d{7,8}$"
The correct format is: "Xxxx-xxxxxxx", "xxxx-xxxxxxxx", "xxx-xxxxxxx",
"Xxx-xxxxxxxx", "XXXXXXX", "XXXXXXXX".
Verify ID Number (15-bit or 18-digit): "^d{15}|d{}18$"
Verify 12 months of the year: "^" (0?[ 1-9]|1[0-2]) $ "The correct format is:" 01 "-" 09 "and" 1 "" 12 "
Verify one months of 31 days: "^ (0?[ 1-9]) | ((1|2) [0-9]) |30|31) $ "
The correct format is: "01" "09" and "1" "31".
Matching regular expressions for Chinese characters: [U4E00-U9FA5]
Match Double-byte characters (including Chinese characters): [^x00-xff]
A regular expression that matches a blank row: n[s|] *r
Regular expression matching HTML tags:/< (. *) >.*|< (. *)/>/
Matching a regular expression with a trailing space: (^s*) | (s*$)
Regular expression matching an email address: w+ ([-+.] w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *
A regular expression that matches URL URLs: http://([w-]+.) +[w-]+ (/[w-/?%&=]*)?

　　(1) Application: Computes the length of the string (a double-byte character length meter 2,ascii character count 1)

String.prototype.len=function () {return This.replace ([^x00-xff]/g, "AA"). Length;}

　　(2) Application: JavaScript does not have a trim function like VBScript, we can use this expression to implement

String.prototype.trim = function () 
{return 
this.replace (^s*) | ( s*$)/g, ""); 
 

　　(3) Application: The use of regular expressions to decompose and transform IP addresses

The function ip2v (IP)//IP address is converted to the corresponding value 
{ 
re=/(d+). d+). (d+). (d+)/g//matching the regular expression of an IP address 
if (re.test (IP)) 
{return 
Regexp.$1*math.pow (255,3)) +regexp.$2*math.pow (255,2　　) +regexp.$3*255+regexp.$4*1 
} 
else 
{ 
throw new Error ("not a valid IP address!") 
} 

　　(4) Application: JavaScript program to extract filename from URL address

S= "http://www.9499.net/page1.htm";
S=s.replace (/. * *) {0,} ([^.] +). */ig, "$");//page1.htm

　　(5) Application: Using regular expressions to restrict the input of text boxes in Web Forms

Only Chinese can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^u4e00-u9fa5]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^u4e00-u9fa5]/g, ') "

Only full-width characters can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^uff00-uffff]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^uff00-uffff]/g, ') "

Only numbers can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^d]/g,") onbeforepaste=
"Clipboarddata.setdata" (' Text ', Clipboarddata.getdata (' text '). Replace (/[^d]/g, ') "

Only numbers and English can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[w]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^d]/g, "

The above content is the entire narration of this article, hope everybody likes, if everybody has the better knowledge about regular expression, can share Oh.