javascript check if input empty or whitespace

I. OverviewStrings are almost everywhere in Javascript. When you process user input data and read or set DOM object attributes, there are more strings when operating cookies .... The core part of JavaScript provides a set of attributes and methods

JavaScript Form ValidationHTML form validation can be done through JavaScript.Automatic validation of HTML formsHTML form validation can also be done automatically through a browser. Nternet Explorer 9 and earlier IE browsers do not support forms

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

JavaScript Regular Expressions1. Using the JS regular expression, first of all to understand the JS regular expressions commonly used symbols, such as: /.../ Represents the beginning and end of a pattern ^ Match

Save the following code as Common. js Class library function: 1. Trim (str) -- remove spaces on both sides of the string 2. XMLEncode (str) -- encode the string in XML format. 3. ShowLabel (str, str) -- mouse prompt function (display character,

javascript|js| Function | Scripting JavaScript can play a big role in web programming by writing some of the most common features into JavaScript libraries. Save the following code as Common.js Class Library Features: 　　1.Trim (str)--Remove the

　 1. Trim (STR) -- remove spaces on both sides of the string 　　2. xmlencode (STR) -- encode the string in XML format. 　　3. showlabel (STR, STR) -- mouse prompt function (display character, prompt character) You can set the font, color, size,

First, JavaScript regular correlation methodStr.match (RegExp) functions similarly to regexp.exec (str).Str.search (RegExp) functions similarly to regexp.test (str).1. String.prototype.match ()Retrieves a match and returns an array (no g) that

Save the following code as Common.js Class Library Features: 1.Trim (str)--Remove the spaces on either side of the string 2.XMLEncode (str)--XML encoding of strings 3.ShowLabel (STR,STR)--Mouse prompt function (display character, prompt

PHP Tutorial Configuration Chinese Narration Let's see what you see, php.ini. [PHP] ;;;;;;;;;;;; WARNING;;;;;;;;;;;;; This is the default settings file for new PHP installations.; By default, PHP installs itself with a configuration suitable for;