javascript - What does the ! (exclamation mark) mean before selector in jQuery -

-

इस सवाल का पहले से ही एक उत्तर है: < / P>

  • 2 जवाब

मुझे पहले से ही पता है कि < कोड>! को सामान्यत: "code" नहीं , नहीं , और null में जावास्क्रिप्ट में अभिव्यक्त करने के लिए उपयोग किया जाता है।

लेकिन jQuery के चयनकर्ता से पहले उद्गार चिल्लाना क्या मतलब है? 

  यदि (! $ ('चयनकर्ता')। हैक्सेल ('कुछ')) {कुछ करो}  < 
 
 
 
 
 
 
 यह एक बूलीयन को अस्वीकार करता है। 
 
 अर्थ: 
 
 
 
 
 और 
 
 
 गलत हो जाता है 
 
 
 
 इस उदाहरण में इसका मतलब है: 
 <पूर्व>  यदि (! $ ('चयनकर्ता')। हैक्लास ('कोई चीज़    हैक्लासेल  फ़ंक्शन के परिणाम पर। ऐसा है जैसे आपने ब्रैकेट्स का उपयोग किया है (लेकिन आपको ब्रैकेट्स का उपयोग नहीं करना है, जावास्क्रिप्ट जानता है कि इसका मतलब है)। 
 
 ! ($ ('Selector')। हैक्लास ('कुछ' ) / * उदाहरण के लिए रिटर्न सही * /) / * अब यह झूठी है * /

Comments

Post a Comment

Popular posts from this blog

Folder list php -

-
I want to list folder names in the list. There is a file to show the folder name. There is already a problem, please do a test. Another code would be OK. & lt ;? Php function getFileList ($ folder name, $ fileType = "") {if (substr ($ folderName, strlen ($ folderName) - 1)! = "/") {$ Folder name. = '/'; } Foreach (Globe ($ folderName. '*'. $ FileType) $ filename) {if_dir ($ filename)) {$ type = 'folder'; } And {$ type = 'file'; } Echo str_replace ($ folderName, '', $ filename. ' '); }} // call function getFileList ('folder name'); // List of all files? & Gt; & Lt; Select class = "form" name = "userlevel" size = "1" & gt; & Lt; Option value = "& lt ;? php getFileList ('theme') ;? & gt;" & Gt; فولدر 1 & lt; / Options & gt; & Lt; Option value = "& lt ;? php getFileList ('theme') ;? & gt;" ...
Read more

objective c - How to open front/back camera at the same time in iOS developing? -

-
I want to use the front and rear camera at the same time in iOS development: when I take a photo back After the camera, the front camera can be opened and another can take a photo. By the way, these two photos are in a picture: vertical arrangement. Has anyone done this before? UIImagePickerController to take the picture, and to determine which camera is used Is in. / P> To merge the pictures, I found an example through search (its recommendation in the future)
Read more

GO: Serve static pages -

-
I'm trying to display a static page with Go. Go: Package main import "net / http" function main () {fs: = http.FileServer (http.Dir ("static / house")) Http: .handle ("/", fs) http.ListenAndServe (": 4747", zero)} directory: project / stable home Html edit.html project.go When I run it, the web page displays links to edit.html and home.html instead of displaying a static page from home.html is. What am I doing wrong. Is this the best way to serve files? I know that there are other ways like From the HTML / templates package, but I'm not sure what is the difference between each of these methods and when. Thanks! fancy main () {http.Handle ("/", http.FileServer (Http) .ir ("static")) http.ListenAndServe (": 4747", zero)} You do not need static / home , just Static . and when you do not have index.html in / static , the directory instead Content appears. Just change the name of...
Read more