JavaScript study notes (5) Regular expressions_basic knowledge

Commonly used metacharacters are:
•. Finds a single character, except newlines and line terminators;
•w matches letters, Chinese characters, numbers, underscores and other symbols;
•s matches whitespace characters (including spaces) , tab characters, etc.);
•d matches numbers;
•b matches at the beginning or end of a word;
Commonly used quantifiers are:
•^n matches anything starting with n String;
•n$ matches any string ending in n;
•n matches any string containing at least one n;
•n* matches any character containing zero or more n String;
•n? matches any string containing zero or one n;
•n{X} matches a string containing a sequence of X n;
•n{X, Y} matches A string containing X or Y n sequences;
A simple example, mainly used to verify mobile phone numbers, phone numbers and emails:
Javascript part code:

Copy code The code is as follows:

function isMobile() {
var mobile = document.getElementById("mobile_phone");
var num = mobile.value;
var reg = /^(13[0-9]|186|188|150|151|158|159|147)d{8}$/;
if(num == "") {
alert("Please enter your complete mobile phone number");
mobile.focus();
return false;
} else if (reg.test(num)) {
alert("The format of the entered mobile phone number is correct");
} else {
alert("Please enter the correct 11-digit mobile phone number");
mobile.focus();
return false;
}
}
function isEmail() {
var email = document.getElementById("email");
var email_value = email.value;
if(email_value = = "") {
alert("Please enter your complete email address");
email.focus();
return false;
} else {
var reg = /^[a -zA-Z0-9](w) @(w) (.) (com|com.cn|net|cn|net.cn|org|biz|info|gov|gov.cn|edu|edu.cn) $/;
if(reg.test(email_value)) {
alert("The email format entered is correct");
} else {
alert("Please enter the correct email format") ;
email.focus();
return false;
}
}
}
function isPhone() {
var phone = document.getElementById("phone") ;
var phone_value = phone.value;
if(phone_value == "") {
alert("Please enter the complete landline number");
phone.focus();
return false;
} else {
var reg = /^[(]?0d{2,3}[)]?s*[-]?s*d{7,8}$/; // 010-87989898 01098989898 (0712)8989898 010 - 23343434 The landline numbers in these formats all meet the requirements
if(reg.test(phone_value)) {
alert("The entered landline number is correct");
} else {
alert("The entered landline number has an incorrect format");
phone.focus();
return false;
}
}
}

HTML part code:

Copy code The code is as follows:

mobile phone

mail