jquery - Why does this Javascript object not go out of scope after $(document).ready? -


I have some javascript which manages some dome elements The problem is, I do not understand that Why This works, which is never a good thing, I'm trying to learn more about Object Oriented Javascript and Javascript best practices, so the organization looks a bit awkward.

In fact, I wrap two methods that manipulate the DOM inside a CSContent object. I make an example of that object, content in $ (document). Bind some events to work in and content . However, I am confused as to how these tasks can still be said after $ (document). This does not mean that content has gone out of the scope, and its work is not available? Anyway, here's the code: 

  function CSContent () {var tweetTextArea = document.getElementById ('cscontent-tweet'), tweetTextElement = document.getElementById ('edit-cscontent-cs-content -TV '), charCountElement = document.getElementById (' cscontent-Tweet-charactercount '); This.toggleTweetTextarea = function () {$ (tweetTextArea) .slideToggle (); }; This.updateTweetCharacterCount = function () {var numOfCharsLeft = 140 - tweetTextElement.value.length; If (numOfCharsLeft & lt; 0) {$ (charCountElement) .addClass ('cscontent-negative-chars-left'); } And {$ (charCountElement) .removeClass ('cscontent-negative-chars-left'); } CharCountElement.innerHTML = '' + numOfCharsLeft + 'characters remaining.'; }; } $ (Document) .ready (function () {var content = new CSContent (); // If the Twitter box is unchecked, hide the text area if ($ ('(edit- cscontent-cs-content- Twitter: check '). Val () === Undefined) {$ (' # cscontent-tweet ') Hide ();} $ (' # edit-cscontent-cs-content-twitter '). ToggleTweetTextarea; // seems useless, but when we delete characters, press the keyboard and keys to fix some weird corruption behaviors. $ ('# Edit-cscontent-cs-content-tweet') .PressPress (content.updateTweetCharacterCount ); $ ('# Edit-cscontent-cs-content-tweet'). ZIP (content.updateTweetCharacterCount); content.updateTweetCharacterCount ();});

I I'm surprised that event handlers like 

  $ ('# edit-cscontent-cscontent-twitter') change (content.toggleTweetTextarea).

Work?

OK that you do not pass content as event handler, but the function present in content.toggleTweetTextarea . And this reference will still exist content no longer exists. There is nothing special about it. You have assigned an object in another variable until it is present in at least one reference to an object, object garbage will not be collected.

Now you can ask that those functions do not have access yet tweetTextArea ? This is actually one stop when the function is created through new CSContent () , then the activation reference of this function will be given to internal functions CSContent.toggleTweetTextarea and CSContent is added to the scope of UpdateTweetCharacterCount . So even if you do not have any reference to content , then the scope of this function is still included in the scope of other functions.

You will not be able to use the object contained in content and after the code has finished, it actually gets out of the scope. is.


-

Comments

Post a Comment

Popular posts from this blog

Eclipse CDT variable colors in editor -

I hope this is a good question to ask here. This programming is related, so I thought it would be better than the superuser, so I am using the CDT C ++ Eclipse plugin. I know how the editor changes colors for some things But is there a way to do that all the variables are different colors? For example in KDEValue, it sets the local variables and square variables in different colors and bold square squares. Can I copy it to CDT? Eclips provides some level of color customization for text editor syntax You can see it on the following: There are many elements, including the Window> Preferences> C / C ++> Editor> Syntax color code that can be changed, assembly, Comments, Preprocessor and Doxian Under the code, it is possible to change the color of some variable types, such as global variables, local variable announcements, local variable references, and parameter variables. But I do not think the code is capable of changing the color of each variable declared....
Read more

AJAX doesn't send POST query -

$ (दस्तावेज़) .ready (function () {function ajaxselectrss (rssurlvar) {var ajaxRequest; // वेरिएबल जो अजाक्स को संभव बनाता है! कोशिश करें कि {// ओपेरा 8.0+, फ़ायरफ़ॉक्स, सफारी अजाक्स अनुरोध} = नया एक्सएमएलएचटीपीआरइवेस्ट ();} कैच (ई) {// इंटरनेट एक्सप्लोरर ब्राउज़र्स {ajaxRequest = new ActiveXObject ("Msxml2.XMLHTTP");} पकड़ो (ई) {try {ajaxRequest = new ActiveXObject ("Microsoft.XMLHTTP");} कैच (ई) {// कुछ गलत चेतावनी ("आपका ब्राउज़र तोड़ दिया!"); वापसी झूठी;}}} // एक बनाएं फ़ंक्शन जो सर्वर से भेजे गए डेटा प्राप्त करेंगे ajaxRequest.onreadystatechange = function () {if (ajaxRequest.readyState == 4) {var ajaxDisplay = document.getElementById ('news'); ajaxDisplay.innerHTML = ajaxRequest.responseText;}} / / Var rssurlvar = $ (this) .attr ("title"); var queryString = "rurl =" + rssurlvar; var urltofile = "rssget.php"; ajaxRequest.open ("पोस्ट", urltofile, सच); ajaxRequ Est.setRequestHeader ("सामग्री-प्र...
Read more

wpf - Custom Message Box Advice -

Well, I'm using a custom window box that comes with some custom control boxes that accompany the text The producers who are displayed are called. I have a defined event, which has been subscribed through the original class, it gets burnt when clicking on the button. However, I can not see how to use it effectively, I would like to return one yes, whether yes or not, but obviously my code will continue to execute, so this Below is some example code to clarify the problem that the method has subscibed by clicking on the button. Message box window Public partial class custom message box: window {public representative message messagebox object sender, event events e); Public event messagebox handler messagebox document; Public Customs Box () {Initial group (); } Public Customsbox (String Message) {InitializeComponent (); This.txtdescription.Text = Message; } Public Customsbox (String Message, String Title, String First BTNtext) {Initialization (); This.lbltitle.Content =...
Read more