Clearing Variables For Garbage Collecting?
Jul 6, 2010
What do you think it would be the best way in Javascript to clear / delete / unset a variable after usage so that the garbage collector can free some extra memory?
Im just setting variables to null like this:
HTML Code:
var useless = "Tomato: 2Kg";
useless = null;
var DIV = document.createElement("DIV");
DIV = null;
I don't know if this is exactly the best way but at least the variable is set to null and maybe it becomes eligible for the garbage collector (correct my if I'm wrong, I'm just guessing).
If I use delete() the variable is not actually deleted and the value is still accesible.
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Nov 29, 2010
Ive got a collection of forms all with check boxes, its basically a coffee menu with four sections.
Say for example the user selects (clicks check box) a small cappuccino, a latte, and an espresso, how can i get the input names (name+size of coffee) to appear with the value (cost of coffee) in another div so i can then calculate sub-total, add vat etc
So far ive only managed to get the users selections to appear where i want using jQuery serialize, however im having a little trouble picking out the values to carry out calculations on them.
note : this is a made up project for a fake client and cant involve any server side scripting.
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Mar 9, 2007
I'm working on an Ajax library that I plan to use on several upcoming
projects. Everything seems to work just great...
Now I want to get into the finer aspects of checking things... How
much memory am I using, are my objects making themselves available for
garbage collection adequately, etc.
Are there tools you can recommend (especially for IE and Firefox) that
I can use to get this information?
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May 2, 2009
I've written some functions that seem to be able to handle parallel AJAX requests. However, I am not sure if they would work under all circumstances.My idea was to create a separate object for each AJAX request in order to bind the right handler function to the appropriate .onreadystatechange. I have used an array to store references to the created objects so that they would not be garbage collected as long as needed (see the lines commented out below). I have noticed, however, that everything works nicely even if I don't save these references -- so, with these lines commented out.
My question basically is whether it is safe to do so, and what prevents these objects from being deleted by the garbage collector. As both the event and the handler function appear to be in the same object, I think it will not stop the garbage collector.
In my code, ajax_req() is called to make a request; it will create the new ajax_abs object whose constructor takes care of the rest.
// ajaxrequests=new Array();
function ajax_abs(method,page,str,dest,todo,myno){
function init(){
[code]....
Furthermore, is it possible to tell the interpreter after the request succeeds, that now it should garbage-collect the object?
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Jun 22, 2010
I am trying reload a div on a page with content from another page using ajax.I am able to do this but the problem is that I need to wait for the page (that I am sending an ajax request to) to finish inputing all the relevant html before it is shown on the page calling the ajax otherwise the re-load of the div will not be up-to-date.
(Here is my code)
$('.addbskt').click(function(){
$.ajax({
type: 'GET',
[code]....
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Jul 12, 2005
Have an array l am building up during end user selections. There is an option to clear all selections, how do l then clear the array?
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Dec 1, 2005
i'm having some problems getting innerhtml to clear on mozilla, but it
works fine in ie. my page is setup such that i have a div:
<div id="otherModel"></div>
on a select from a combo box, in my javascript i execute:
div = document.getElementById("otherModel");
depending on what's selected in a combobox, i execute:
var inner2 = "<p>Other Model:<br />";
inner2 = inner2 + "<input type='text' id='otherModel' ";
inner2 = inner2 + "size=ཐ' maxlength=ཚ' value='Enter Model'>";
div.innerHTML = inner2;
or simply:
div.innerHTML = "test";
This all works fine independantly; it'll either fill with my textbox,
or the test string. but if the innerhtml is filled with the text box,
then i make a new selection that fills it with "test", it doesn't clear
out the text box.
If i replace the variable inner2 with simple text, everything seems to
work great (but i need a text box!).
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Jun 9, 2009
how can i clear the feilds in using jquery just like reset form in html.
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Dec 7, 2009
I have a table with numerous textareas that I am able to clear once - the first time the textarea is clicked the default value is cleared and everything is OK.However, at a certain point the user might press a 'Clear' button linked to a function I wrote to reset the values back to the defaults. At this point clicking into the textarea does not clear it.
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Nov 17, 2010
I'm trying to have a textbox clear after it has been filled and submitted. this is my form look....
<form action="" name="webForm" id="webForm">
<div id="title0" class="pageTitle">Enter Student Dropping A Course: </div>
<div id="fieldName">Name: <input type="text" id="fName" name="fName" size="40" maxlength="60" /></div>
[Code]....
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Apr 3, 2004
How do I clear a list menu?
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Apr 9, 2001
I have a page with multiple text fields, each of which has an example for an initial value. I've added the appropriate code so that onFocus() the example is cleared away, and a blank field is left behind. Trouble is, I only want that to happen once, so that the field isn't cleared if the user attempts to edit what they wrote earlier. Anybody know of a way to do that with only a few lines of code? Here's my existing code:
Code:
<script language="JavaScript">
<!--
function clearField(fieldName) {
fieldName.value = "";
}
// -->
</script>
<p>Person's Name: <input type="text" name="name" size="30"
value="John Smith" tabindex="2" onFocus="clearField(this)"></p>
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Jun 2, 2005
I have a form with two input fields - 'name' & 'research'. What I'd like is for 'name' to be cleared when the user clicks in 'research' & visa versa. I've tried to do this by implementing the code in Sitepoint's excellent new DHTML Utopia article, but without success. I'm guessing that I should be using the onblur event, but am not sure how to go: Code:
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Sep 6, 2007
I have a page with 5 sets of form fields. Each field set has a checkbox that if checked will allow users to utilize it. I want to clear the given field set when the user un-checks the check box. As you can see in the code below this method will make for a very long and cluncky script, I would like to make it more generic.
<script>
function clear() {
window.document.roles.foo1.checked = ''
window.document.roles.foo2.checked = ''
}
</script>
<input class="checkBox" />
<input checked name="foo1" type="checkbox" class="checkBox" />
<input checked name="foo2" type="checkbox" class="checkBox" />
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Mar 24, 2010
I have a working script here regarding generating a <div> that contains a <input> text. My concern is whenever the checkbox is unchecked, the <input> type hides but the value is still there (the one inputted)
Here is my code for reference:
HTML Code:
<script type="text/javascript">
function showCheckBoxDiv (DivName, box) {
vis = (box.checked) ? "block" : "none";
[Code]....
Say for example, I click the checkbox, the field appears, I inputted something on the field, but I unchecked the checkbox, when I click again the checkbox the value I input is still in the field. Is there any way, it can be cleared as soon as the checkbox is unchecked?
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Jul 23, 2005
If I fill out the textfields properly with Name, Email etc in a row it
is fine. But if I fill out, for example, my Name, then tab twice, it
clears my entered value. How do I stop this?
All I want the script to do is that when the cell is blank or
whitespace, put the necessary text in the field, else, continue as
normal. Code:
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Jul 23, 2005
I have a couple of different webpages that need to call a function to
clear the textbox onFocus of the textbox. I'm wanting to use one
function that I can call from a javascript include file (rather than
having multiple versions of the function all through the site).
So far i've tried the following:
function clearfield(poForm,poElement)
{
if (document.forms[poForm].poElement.value == "Type Search Here...")
document.forms[poForm].poElement.value = "";
}
where the passing page calls the function as:
clearfield('formname','formelement');
but just get errors.
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Jul 14, 2009
I'm making a small web app and I want to upload files on the server. Everything works fine, but what I want to achieve is to remove any special chars in the value name.My value name is 'NewFile'. I want to remove any special chars from the name before the upload process, ex.: remove things likeAll I want to keep in the string is small caps english letters (no etc.) and numbers. no spaces. I want to keep underscores and dashes too ( - and _ ).I can't seem to get it.That it what I used;
Code:
NewFile = NewFile.replace(/[^a-zA-Z 0-9]+/g,'');
I'm not very good in javascript, I took this code on the web.
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Jan 17, 2011
i wanna make a confirmation alert box (jquery i suppose) then when triggers when someone click log out. on cancel it stays there but on ok it destory the session and cookies and logout.
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Feb 6, 2011
On this page http://bit.ly/gAajO3 I have a comment form and would like the input and textarea contents to turn to blank when a user clicks on them, however this is not working for me. Would like to know what is going wrong if someone can spot it.Also on submit I want the input and textarea to be cleared if their value is 'Please type here'. This is working on the name input and textarea, however it seems the email field is not being cleared,
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Sep 8, 2005
I have an object that has a fade method
Code:
ImageHandler.prototype.fade = function()
{
var oThis = this;
if(// some conditions)
{
window.clearTimeout(oThis.timer);
}
// the this.timer is set to null in the constructor.
this.timer = window.setTimeout(function(){ oThis.fade() }, 150);
}
Problem I have is that the timer is not cleared. The if when the timer should be cleared works fine, so I took it out in this example to minimize the code.
I also tried window.clearTimeout(this.timer) with no luck. Any ideas?
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Jul 4, 2010
i am currently developing a java script based calcualtion form that will take the data entered in to a few text boxes, calculate a result and output.
I can get the results I want but my script is falling down on the validation code I have.
When the script is run it correctly picks up the validation failures and displays an alert prompt however once a user OK's the prompt the page then clears itself of all the user input data , I dont want this to happen.
what I want it to do is to throw the validation error and then let the user edit the data they had input.
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Mar 30, 2011
I installed a JS form dependency script. Basically if a checkbox is checked Field A will disappear and Field B will take its place.The script appears to work fine. The problem I am having is this. If someone submits the form using the Field B entry and then they need to submit a form using the Field A entry, the Field B entry is still being passed even though is it is not displayed and Field A has a value in it!So I guess my question is, how do I flush out the form field after the form is submitted? This is just happening with the fields where there is the JS Form Dependency script involved.
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Aug 17, 2011
So I have a form with a few tables in it. One of these tables is to enter new values, and the rest of the tables are to update existing values. I need to be able to empty all values of elements within the table for entering new values on a button click, but I'm having trouble doing this with jquery.
I'm trying to find all elements inside of the table with id of "new_details" and then set all text box values to "" and uncheck all checkboxes but I'm not getting anywhere.
[Code]...
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Feb 19, 2010
I need to clear the default value from a textarea when a user clicks on the textarea and then replace it if the user clicks away from the textarea without modifying it. I have managed to accomplish this with the textfields in my forms but I am struggling to get the textarea element to mimic this behavior. Here is the script I am using:
[Code]...
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Nov 24, 2010
This is some of the script that I have and it works well. The story is that I have a drop down list and depending on the selection a different set of text is displayed below the list.
if (Val == "general")
{
document.getElementById('Link0').innerHTML="<font size=2><a Href='http://www.web1.com/'>web 1</a>"
document.getElementById('Link1').innerHTML="<font size=2><a Href='http://www.web2.com/'>web 2</a>"
However when the selection runs this part of the code:-
[Code]....
The "web 3" text is placed under where the 'Link0' text would have been if there had been some. So basically what I need to do is set the 'Link0' text to nothing and have the 'Link1' text sit in its place. I know I could just put the 'Link1' text in the 'Link0' element but I have other controls on the screen that mean I need to run it as it is.
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