Regular expressions in JavaScript

Some of the functions of regular expressions:
1. Test a pattern for a string. For example, you can test an input string to see if there is a phone number pattern or a credit card number pattern in the string. This is called data validation
2, replace the text. You can use a regular expression in your document to identify specific text, and then you can either delete it all or replace it with another text
3. Extracts a substring from a string based on pattern matching. Can be used to find specific text in text or input fields

17 Regular Expressions for javascript:
"^\\d+$"//nonnegative integer (positive integer + 0)
"^[0-9]*[1-9][0-9]*$"//Positive integer
"^ ((-\\d+) | (0+)) $ "//non-positive integer (negative integer + 0)
"^-[0-9]*[1-9][0-9]*$"//Negative integer
"^-?\\d+$"//Integer
"^\\d+ (\\.\\d+)? $"//non-negative floating-point number (positive floating point + 0)
^ ([0-9]+\\]. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*)) $ "//positive floating-point number
"^ ((-\\d+ (\\.\\d+)?) | (0+ (\\.0+)?)) $ "//non-positive floating-point number (negative floating-point number + 0)
^ (-([0-9]+\\]. [0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\\. [0-9]+) | ([0-9]*[1-9][0-9]*))) $ "//negative floating-point number
^ (-?\\d+) (\\.\\d+)? $ "//floating-point number
"^[a-za-z]+$"//A string consisting of 26 English letters
"^[a-z]+$"//A string consisting of 26 uppercase letters in English
"^[a-z]+$"//String consisting of 26 English letters in lowercase
"^[a-za-z0-9]+$"//string consisting of a number and 26 English letters
"^\\w+$"//A string consisting of numbers, 26 letters or underscores
"^[\\w-]+ (\\.[ \\w-]+) *@[\\w-]+ (\\.[ \\w-]+) +$ "//email address
"^[a-za-z]+://(\\w+ (-\\w+) *) ( \\w+ (-\\w+) *) * (\\?\\s*)? $ "//url

A few small examples of simple information validation using regular expressions in javascript:

1, using the JS regular expression to determine whether it is 0-9 of the Arabic numerals

function Regisdigit (fData) {    var reg = new RegExp ("^[0-9]$");    Return (Reg.test (FData));}

2, using the JS regular expression to get the length of the string

function Regdatalength (fData) {    var vallength = fdata.length;    var reg = new RegExp ("^[\u0391-\uffe5]$");    var result = 0;    for (i=0; i< vallength; i++)    {        if (reg.test (Fdata.charat (i)))        {            result + = 2;        }        else        {            result + +;        }    }    return result;}

3, JS judge whether the value

function Regisnumber (fData) {    var reg = new RegExp ("^[-]?[ 0-9]+[\.]? [0-9]+$ ");    Return Reg.test (FData)}

4, JS verify email is correct

function Regisnumber (fData) {    var reg = new RegExp ("^[-]?[ 0-9]+[\.]? [0-9]+$ ");    Return Reg.test (FData)}

5, JS to determine whether the phone number is correct

function Regisphone (fData)   {       var reg =/^ (\+86)? ( 1[0-9]{10}) $/;       Return Reg.test (FData);   }

Note: The above content from my online simple collation

Regular expressions in JavaScript