javascript check if string 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 is a world-leading programming language for Web development, mobile application development (PHONEGAP, Appcelerator), server-side development (node. js and Wakanda), and more. JavaScript is also the first language for many beginners to

JavaScript is a world-leading programming language for Web development, mobile application development (PHONEGAP, Appcelerator), server-side development (node. js and Wakanda), and more. JavaScript is also the first language for many beginners to

JavaScript is a world-leading programming language for Web development, mobile application development (PHONEGAP, Appcelerator), server-side development (node. js and Wakanda), and more. JavaScript is also the first language for many beginners to

JavaScript is a world-leading programming language for Web development, mobile application development (PHONEGAP, Appcelerator), server-side development (node. js and Wakanda), and more. JavaScript is also the first language for many beginners to

JavaScript is a world-leading programming language for Web development, mobile application development (PHONEGAP, Appcelerator), server-side development (node. js and Wakanda), and more. JavaScript is also the first language for many beginners to

Http://mp.weixin.qq.com/s?src=3&timestamp=1474692926&ver=1&signature= Agi3w5rkmvc6ggbdtxhvogejvpgmg8wy9eounmkmoy4vgptu-neqypxdwiq2m8nqsm61wrt0cxfspaxgzepop1mss6rjexrbojykf2v84zfgfpjkei3 *ulskszhfp*w8g6fefmhcctlazzieeswvba==JavaScript is a

1. Be sure to use the first time you assign a value to a variablevar / let / constKey wordsVariables are not declared and are directly assignable, and as a new global variable by default, avoid using global variables as much as possible.2. Use = = =

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

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,