javascript check if string contains only letters and numbers

restricting text boxes with regular expressions can only enter numbers, decimal points, English letters, Chinese characters and other types of code 2. Only numbers can be entered and the decimal point may be lost. 3. Number and decimal method two 4

function validpsw () {varPassword = $ (". Password"). Val (); varnum =0; varNumber =0 ; varLetter =0 ; varBigletter =0 ; varchars =0 ; if(Password.search (/[0-9]/) != -1) {num+=1; number=1; } if(Password.search (/[a-z]/)! =-1) {num+=1;

/* Determines whether the specified content is null. If it is null, a warning box is displayed. */ Function isEmpty (theValue, strMsg ){ If (theValue = ""){ Alert (strMsg + "cannot be blank! "); Return true; } Return false; } /* Chinese judgment

Javascript Regular Expression detection only contains Chinese characters, numbers, letters, and underscores. It cannot start or end with or after an underscore, for more information, see javascript Regular Expressions. Only Chinese characters,

Javascript Regular Expression detection only contains Chinese characters, numbers, letters, and underscores. It cannot start or end with or after a hyphen. I encountered a user name check problem and checked it. The following is a summary example:

JavaScript regular detection contains only Chinese characters, numbers, letters, underscores can not be underlined at the beginning and end, the need for friends can refer to the followingJavaScript regular detection only contains Chinese characters,

We recommend that you search for and collect many common js judgment functions. We recommend that you search for common js judgment functions. *Determines whether the specified content is null. If it is null, a warning box is displayed.*/Function

Summary of little knowledge about JavaScript performance optimization, and javascript Performance Optimization With the development of the network, network speed and machine speed, more and more websites use a variety of client technologies. Ajax is

# The JavaScript authoritative guide notes-part 1thDescription: Printed version: April 2012 1th Edition, September 2016, 17th time printing.The style of the book and "effective Java" very similar, recommended.This note is recorded in reverse order.--

Special characters in regular expressions Character implication \ As a turn, that is, the characters usually after "\" are not interpreted in the original sense, such as the/b/matching character "B", when B is preceded by a backslash/\b/, to