In What Situations Would You 'Pass By Value' And 'Pass By Reference'
Nov 20, 2007
I have been trying to grasp the whole 'Pass By Value/Reference' thing for a few hours now. From what i can make out:
Passing by value will make a copy of the value, pass it as a function argument and the function will store the changes, the original value is not affected. So for example:
JavaScript Code:
var cost = 145;var postage = .3;var a = function() {return cost + postage;} //Using an Anonymous function for this
If you was then to pass the value of 'a' to a function argument it would copy and not change the original value.
If you pass by reference it will change the original value. When you pass a reference to a value through a series of different functions and the value is constantly being changed the change happens on the original value and can be seen outside the function.
The problem is i cannot think of how or why this would be used. I havn't got to develop many large applications so im trying to think of a few situations when passing by reference would be used.
element = xGetElementById(obj.ID+i); position = element;
I need this several times in my script and I am sure it createst quite a lot of overhead. And I would like to pass xGetElementById(obj.ID+i) into an element array. like:
element = new Array(); element[i]=xGetElementById(obj.ID+i);
So I can call back element[i] etc in my script by saving some overhead BUT (there is always a 'but' in my posts ) then:
Anyone know how to pass value from 1 javascript to another javascript?I wanted to pass 1 of the variable in A.asp to B.asp variable. is it possible to do it?
how to pass a value from jsp to javascript both being different files.. ie a.jsp , b.js.. I have a hidden value in jsp i want to get its value in the javascript file
In the new window that just opened called quotescreenwindow.php, I have a button that when clicked, should open yet another window called enrollwindowprime.php (this is the variable I am passing after the question mark).
What I cannot do, is to grab this variable that I am passing to the first window I open and use its content to open the next window.
I am not very experienced and have been piecing this together from various web sites.
To simplify all of this:
Screen A Opens Popup Window B and passes it a variable with a url inside of it.
Popup Window B wants to use the variable with the url to open Pop Up Window C.
I'm trying to use jquery with php by sending out calls and getting values returned, but I need to store them on a variable, but whenever I do that nothing shows this is the code I have now and is not working
$("document").ready(function(){ var cal = $.get("date.php", function(data){
I have a javascript that will take whatever was entered on this form and send it to the new URL (without submitting), but for some reason - it doesn't work anymore. i've changed things around, & probably messed soemthing up.
Code:
$('#cb_ht2').click(function() { // Reset incase Data Changed[code].....
I think i may have messed it when when adding that target-"_parent", it needs to pop a new window
Is it possible to pass the id onChange like in this example instead of the value This is part of a large complex script, and I need the id as seperate function
I have an ajax script that sends a request to a servlet for information to be inserted into a table cell. The servlet then handles the request and replies with something like this:(I took the liberty of removing all the out.println tags)
For some reason, however, all the scripts functions cannot be found on the page. If I attach the <script language='javascript' src='whiteWine.js'></script> on the page then the functions work, but they are used as polymorphism and incorrect information is shown. (There are 3 different scripts with the same named functions, but different implementations).Is there a reason why ajax can't send across scripts?
I'm sure there is a really, really simple way to solve this issue. I'm just not a programmer so I don't know it off the top of my head. I have this script ext.php that accepts a variable ref.[URL]..The problem is that there is also a '?' in the variable ref that I'm using. Like so:[URL]...I suspect because there is another '?' in variable ref, ext.php has a problem with it. I cannot change ext.php or sitename.asp.
So my question is, how can I make this work properly via the url? I've tried using %26 for the '?' as well as the & html escape code, but it still doesn't work.
I am developing application in which i use ajax.but i need to pass more than one variable to url for further processing. I can't use
var url="availabilitycheck.php?t="+value //it works var url="availabilitycheck.php?t="+value+"&hid="+hd1+"&chkin="+chkin; //not valid
How can i send other variables.?? I tried using session that works but it does not work when i integrated it to joomla. So is there any way to pass more variable in url as querystring?
var backgrounds = new Array("images/tiles/pattern_044.gif","images/tiles/pattern_045.gif","images/tiles/pattern_046.gif"); // setEvents is triggered by onload in the body tag function setEvents() { changeBkg();
ok I have a unique problem, I need to pass a variable's value to a function instead of a pointer (reference) to the variable as by the time the function is called (because of the SetTimeout function) the variables value has changed.
I realise that may not be so clear so I've included the long explanation below, please bare with me ... =p
I have a 2 dimensional menu, when you hover over menu item it animates. to exaggerate that it is a menu (from the design it's not immediatly apparent) I decided to add a simple animation for when the page loads where it loops through each menu item and animates it in sequence.
each of the sub menu items are stored in a 2D array (SubMenuItemsArray) and I get the "wave" effect by having a short (60 millisecond) pause between each animation (achieved with Window.SetTimeout).
heres the code, I've set i and j to 0 after the loop to highlight the issue.
Below is a stock script I found which controls a framed environment. My problem is that if a URL has a query string attached, that string does not pass through. Can someone please let me know if and hopefully how, it will be possible to carry a query string through?
This first part here is in the default.asp framed page. Code:
I wonder if anybody can give me a hint about what I have to do to get this working: I am creating a drop down box using the script below. The
result is two text fields; now I want to pass those values, which come from the drop down box, to the next page. The next page should then simply look like this:
Month:
Year:
And the values should be the ones from the drop-down box... I have been staring myself blind about how to get this accomplished. Would be more than grateful if somebody could have a look...here is what I got so far: Code:
