I'm trying to find out how JavaScript manages its memory. In
particular when using the 'new' operator to create an object is it
necessary to explicitly delete this object (before it moves out of scope,
like c++) or does JavaScript clean this up automatically?
What about string varaible which uses concatenation extensively?
JavaScript hides its memory structure.
I know that numbers, booleans, null and undefined are value types
(value is directed saved in a variable).
I want to know:
- How JavaScript distinguishes value types from reference types by
seeing the variable content?
- How many bytes are allocated in memory when I declare the following?
var i;
I can program in JavaScript without understanding them.
But I'm curious.
First the code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title></title>
<script type="text/javascript">
function TextScroll(scrollname, div_name, up_name, down_name, top_name){
[Code]...
When I use mouse wheel in Firefox to scroll contents of the DIV, memory usage in Firefox goes through the roof. Code above is a fully working page, if anyone would like to see what's up, just load it up, and start moving your mouse wheel in the area with text. You don't actually have to scroll the text, just moving the wheel back and forth in that DIV will do. Memory usage will start going up quite fast, and after you stop moving the wheel, it will finally come down a bit after a short while. I've highlighted in red the line where mousewheel event is registered for Firefox. I'm not sure if it's really a problem, but since Opera and IE don't have any strange memory usage, and Firefox does, maybe I did something wrong. In everyday use it shouldn't matter [don't expect to have kilometers of content to scroll], but anyway, it is a bit unsettling.
I would like to not have to write:
.parentNode.parentNode.parentNode.parentNode.parentNode
Instead I would like to just write something like this instead:
.parentNode(5)
to represent that there needs to be 5 .parentNode
All javascripts have two parts: one to insert between head tags and other between the body. Problem is that when you are managing the site with cms you usually can not edit head tag (only main contend in body tag is editable). How to insert corretly javascript in CMS? I have read somewhere that full script can be inserted in body tag, but then there is a danger that the script wont be loaded corretly. Is it true?
View 2 Replies View Relatedi have just started learning & understanding JavaScript. I am just trying to do a small project for my Brother regarding Leave Management, for which its required to Select the From Date & To Date, wherein the Total no. of days should be calculated, excluding the weekends.
I have just worked around to calculate the number of days but i am not sure how to exclude the Weekends. & what if the the Year is a Leap year - So how will i include the Extra days of Feb month. I am using RAD date-pickers to get the Value & split it.
But being a newbie to the Coding world i m really N'joyin the JavaScript....
Just need help regarding this coz i m totally helpless...
I am taking the 2 Dates from 2 Rad Datepickers & diplaying the Number of Days in a Text Box.
Here is My Coding :-
<script type="text/javascript">
function CalcLeaveDays()
{
var
[Code]...
The topic of event handler management has been covered in many places in the past. One location is in the contest by PPK (http:[url]....). The winning submission by John Resig (http:[url]...._and_the_winner_1.html) has a few problems, and the commentary on the site seems to gravitate to the implementation by Dean Edwards (http://dean.edwards.name/weblog/2005/10/add-event2/) after the analysis of the Resig code.I was also able to find a few more implementations on stackoverflow from: Bill Ayakatubby (http:[url]....) and Marco Demaio [url].....
Outside of the JavaScript frameworks, what is generally done for supporting event functionality? There are numerous options each with their own benefits and drawbacks. I'm uncertain of which one to use myself. Is there an undeclared de facto?
is there any way I can get what field has focus in the form? I would
like to trap the "backspace" only if focus is on spesific field.
I would, first, like to know, when someone hits a submit button and a form
is sent, how could you get that form sent as text instead of an attachment?
And second, how do you get the user to be able to browse for an image on
his/her computer and load it to a form?
I am using this browser that came with an sbcglobal account and when
I click on the built in "shopping" button (and others), sometimes i get
a jscript runtime error. It happens often but not always. It is very
annoying. When I launch the debugger I don't know what i am looking at.
My question is. Is there anything I can do to stop this from popping
up? Or is this caused by the source from the site?
Is Javascript build in to the browser or is there someway i could update
it. Would that help?
Would using a different browser help? I think this is sbcglobals own
browser but it might be based on IE.
i nees a scriopt to create a form in which i need to ask 10 questions from users. each question will have two answers. yes or no (radio button). visitor will have to select either yes or no. no question can be left unanswered. above question answers (in same form), there will be data field for user where he will submit his
name, email, ph, address etc. after submitting all fields, visitor will submit. now following will happen.
a. a unique id will be created to be associated with this form
b. his data will be emailed to one email or two emails
c. in next screen, he will see his unique id alongwith results of his questions and answers
d. if he replied all questions as yes, he will be passed
e. if he replied no (even to a single question), he will be failed
I know how to randomize an array but how do I randomize the array below and keep the questions and answers together.
Code:
Okay, how do I write a page with a form so that when I click Submit,
the following happens?
1. The data is submitted (of course)
2. The form is cleared (what I've tried results in the form being
cleared first, resulting in an empty submission), and
3. The cursor goes back to the start of the form, ready for more input
(kind of like how Google puts the cursor in the search box at the
start).
I can't seem to find the answer, and I've been looking on the net for a
few hours already.
Attempting my first bit of JQuery, looking to hide or reveal questions in a form based on the value selected from a drop down list.i.e. select1
"1" Red
"2" Blue
"3" Yellow
I'm following an example where a single value is matched, i.e. if 1 selected reveal question
$(document).ready(function(){
I have a form script that is made up of Text boxes, radio buttons, and drop down boxes. What I am wanting to happen is upon clicking submit at bottom of form, it should run a check to make sure all questions have been answered. So far it catches all the text boxes, but it's not catching the radio buttons or drop down boxes.. I have all of this under 1 form name ( is this where my problem is located? do I need to seperate into different form names based on type?) I am not wanting the answer given too me ( at least not yet ). I have done a search for multiple types of validation. But nothing seemed to clcik... Also Do I need another validation set up point for the Month, Date, year Drop down boxes?
[Code]...
i'm in need of a DHTML program for design tourism management program.. Since i don't have idea on it i unable to design it.
View 1 Replies View RelatedI need help with this code. its a counter.
var count= 0
function onm() {
atextbox.value=ffee
count++
setTimeout(onm(),100)
}
And in the body:
<body onload="onm()">
<input type="text" value="0" name="atextbox">
</body>
I get always an error: Out of memory
I've been putting together a small pet project. Once it was finished i realised it had a gigantic memory leak inside of it. I tried to read up on the subject, but couldn't find the source of the problem via the articals.
This site is very simple, so I'd think idenifying (and hopefully fixing) the problem would be easy. Here is the relavent portions of JS (followed by links to the full page incase you need to see that): Code:
I was wondering how good is JavaScript with memory management. I have
an object called MANAGER that has a list of other objects, each one
managing a single DOM nodes, etc. In my implementation of
MANAGER.reset(), I simply recreate my MANAGER.object_list = new
object(); and do a single MANAGER.domnode.innerHTML = '' as apposed to
getting my hands dirty. Is my app leaking memory?
Internet Explorer leaks memory when I update a div container using
innerHTML, this does not occur in firefox. This would not be a problem
except the webpage is required to be left on for weeks on end without
being restarted. I presume the issue with innerHTML is that Internet
Explorer apparently parses what you give it and then decides on how to
construct the dom elements itself, so never truely creates what you
give it.
I know that the innerHTML is the problem as I have successfully
narrowed down the leak to that line. It only leaks memory when I assign
content to the innerHTML of my containing DIV. Appending a text node,
for example, with the exact same information to the same div does not
leak. Note I have also tried using such existing AJAX packages like
Prototype etc. but to no avail.
I need to do it this way as my XML documents are styled using an XSL
stylesheet and then transformed using transformNode [I will omit
details regarding firefox as there is no problem there]. I have looked
into transformNodeToObject as a way to get a dom object that I
originally assumed could be appended [as a child] to my containing
element. This did not work and gave me compatibility errors.
I suppose I am either looking for someone who has solved this problem,
or who has an acceptable work around. Or someone to say that it cannot
be solved.
I am using javascript to load and parse a big xml file (around 1 mb) save some values to an array and draw a picture using google Flot. Unfortunately, this causes the browser to crash! Is there a way to clear the memory of the browser?
View 2 Replies View RelatedI am developing a simple image editor in an HTA (for a special use-case). Because it is an HTA, it runs in IE only (IE7 to be precise).
Everything is working great so far, however, because I am loading the same img src file over after every edit, I had to attach " + Math.random();" to the image src so that the updated image is displayed.
This has lead to some pretty severe memory issues, as each time I make an edit, it caches another image. Under normal operation, my app uses under 20MB with a single image loaded, however after every edit it adds about 3MB. After a few minutes of testing I have had it consuming over 200MB!
Is there another way to use the same file name, same image src, etc, but have the browser re-read the file before displaying it again rather than using a cached copy.
Alternately, is there a way to make the browser forget about the other copies it has in memory to keep memory usage under control.
I'm trying to make a calculator in HTML/Javascript but I'm having trouble with the memory buttons. Here is the code:
<html>
<head>
<title>Env X Software | Env X Online Calc</title>
[code]....
I'm writing a very complex javascript application and I'd like memory usage to be as low as possible, so I've got a question about objects.
I'm using jQuery and my code is a bunch of jQuery plugins that interact with eachother. Will there be a difference in memory usage if I declare functions like this:
I haven't written anything in javascript as complex as I'm about to write, so I never worked with objects. As far as I understand, $.fn.whatever will add function to prototype, while $.whatever will add function only to one entry of jQuery object.
So question comes down to this: when jQuery object is being created, are functions in it being copied (meaning increase in memory usage) or does javascript only make references (meaning no significant increase in memory usage) to one main entry of that function in prototype?
what is DOM maximum memory size? is Diff from browser to Browser?
View 1 Replies View Relatedtake a look at the below code. The below code is small representation of a bigger system.
HTML Code:
<html>
<head>
<style type="text/css">
</style>
[Code]...
However the problem is that once the tabs/iframes are removed the browser does not release the memory. This happens both in IE8 and FireFox. So over a period of time the memory consumed by the browsers are huge because of the creation and deletion of new tabs/iframes and the application slows down. Is there a way to make the browser release memory when an iframe is removed.