Resolved Undefined Variable In Function - Scope?
Oct 27, 2009
I'm just starting out with Javascript as a development language and this will probably be a relatively simple problem for someone to solve for me.
I am trying to access a variable (this.bodyEl.innerHTML) from within a function but get an error message indicating that it is "undefined". I know that it is a valid variable because I call it elsewhere outside of the inner function itself.
I'm sure this is just a scope issue, but I'd welcome any suggestions on how to solve it with an explanation of where I've gone wrong if you have the time.
[Code]...
View 2 Replies
ADVERTISEMENT
Oct 30, 2006
I think I've had JavaScript variable scope figured out, can you please
see if I've got it correctly?
* Variables can be local or global
* When a variable is declared outside any function, it is global
regardless of whether it's declared with or without "var"
* When it is declared inside a function, if declared with "var", it's
local, if not, it's global
* A local variable that is declared inside a function is local to the
whole function, regardless of where it is declared, e.g.:
function blah() {
for(var i ... ) {
var j ...
}}
i and j will both be visible within blah() after their declaration.
* the notion of "function" in this context also applies for this kind
of construct:
var myHandler =
{
onClickDo: function()
{
in the sense that whatever one declares inside onClickDo with "var"
will only be visible inside onClickDo. What else, am I missing anything?
View 4 Replies
View Related
Mar 4, 2009
I have been trying to figure this out for a few days now and have finally come to the point where I think I got it but may just need a little push to get what I want.
Heres the situation:
I have this function that uses ajax to access a database and returns the results in the responseText. That part is working fine, I have confirmed that the responseText contains the information that I need
**************code*****************************************
//new ajax already created and assigned to the variable xmlhttp//
var response_recieved = "some data";
function get_answer(Table_Name, Field_Name, Data_Type) {
[Code]....
As evidence by my posting, this is not working correctly. The variable response_recieved is coming up undefined outside of the callback function assigned to the onreadystatechangeproperty.
Based on the information that I have gathered online from various forums, I believe this issue has to deal with a problem with closure in the callback function assigned to onreadystatechange property. I don't think it has any. Based on the fact that there is no anonymous function in that function. But my problem is that the call back function is anonymous itself... I think???
get the variable response_recieved to survive outside of this function.
View 2 Replies
View Related
Oct 1, 2010
[code] Hide from browsers that do not understand Javascript.The addLoadEvent function adds functions to the window.onload command to load multiple functions at startup function addLoadEvent(func)[code]When the page loads I get the nice alert box that says loading and then one that says count equals 0.When i click my edit list drop down and choose modify I get a message box that reads count equals in edit function 0.If I type text in the textbox and leave the text box I get an alert box that reads count equals in subcheck function Undefined and then another one that says NaN.
View 7 Replies
View Related
Jul 23, 2009
I've written a function to format a number. It strips dollar signs and commas, converts to a number, and sets the number to two decimal places.However, I get the error message "amountNum is undefined". It occurs right where I use the replace command.[code]I am calling the function with this line of code:[code]
View 16 Replies
View Related
Jul 20, 2005
If I do . . .
myForm=document.tstForm;
function initialSetup(){
myForm.fld01.value="Test 01"
myForm.fld02.value="Test 02";
myForm.fld01.focus();
}
Then, in the body tag, I do onLoad="initialSetup()",
the script doesn't work and I get a "myForm has no properties" error
I know it'll work if I move it within the function, but I figured a
global variable would retain its value within the function. Why not?
View 2 Replies
View Related
Jul 23, 2005
Given the following working code:
function attributes() {
var attr1 = arguments[0] || '_'
var attr2 = arguments[1] || '_'
return (
function (el1, el2) {
var value1 = el1[attr1] + el1[attr2];
var value2 = el2[attr1] + el2[attr2];
if (value1 > value2) return 1;
else if (value1 < value2) return -1;
else return 0;
}
);
}
var a = [
{ a:'smith', b:'john' },
{ a:'jones', b:'bob' },
{ a:'smith', b:'jane' }
];
a.sort(attributes('a', 'b'));
for (var i =0; i < a.length; i++) {
document.write(a[i].a + ', ' + a[i].b + '<br>');
}
My question is, are attr1 and attr2 guaranteed to exist through
the lifetime of a.sort(attributes('a', 'b'))?
As I understand it, the anonymous inner function reference I am
returning is a property of attributes(). As such, when I return a
reference to the anonymous inner function, the outer attributes()
function must continue to exist (as must attr1 and att2) until
there are no further references to the inner anonymous function.
As a result, there is no danger of attr1 or attr2 "disappearing"
during the repeated calling of the anonymous inner function.
Is my explanation basically correct, or am I deluding myself and
I'm just lucky that the garbage collector hasn't recovered attr1
or attr2 while the sort is still going on? In other words, is the
behaviour I'm seeing consistent and predictable, or should I
change my approach?
View 3 Replies
View Related
Mar 31, 2010
I would like to ask your help regarding this damned error message that comes out only in Internet Explorer and makes impossible to submit the form.
The javascript code is:
function checkForm() {
var cname,
[code]....
View 4 Replies
View Related
Jun 14, 2010
I've created a jQuery script that uses a switch statement. However, my experience with it, relative to variable scope, doesn't seem to follow the logic.According to the JavaScript/jQuery theory, a global variable was accessible (meaning read & write) throughtout any function within any script (one that page).However, apparently that theory wasn't completely true as it pertained to switch statements that contained variables. To illustrate my case in point, I've included a simplistic version of my code:
$("#selector").delegate("div", "click", function(event) {
var testVar = 4;
switch (this.id) {
[code]...
As shown, the variable "testVar" is not accessible from one case to the next case .Furthermore, to add insult to injury, I am seeing the same behavior within the conditional if else statement counterpart to the switch statement.
View 1 Replies
View Related
Oct 17, 2010
I have this web application where users are able to fill out and submit reports. The reports and scripts are part of a whole system, that is, they are used on a couple of different clients written in both vb and c#. This is the web-version of those clients.The scripting language is javascript and is executed using different script engines on the different systems. But for the web-version it is just executed in the browser.The different fields in the report can be accessed by typing:ID1.value. To get ID1 to apply for the input-field with id ID1 I had to in the initfunction of the page write a window["ID1"] = document.getElementById("ID1");
But my problem is when this element change. Cause in the report I have a special element that in the browser is translated to a table-element with a report-field in each cell.When I switch the current row, I need to update the window["ID1"] to equal the correct report field on the selected row. But when trying to access the new variable ID1 from a buttons onclick event it is undefined.<input type="text" id="test" onclick="alert(ID1.value);" />What I think happens is that when the page is first drawn the onclick event is created and as I understand, variables inside an event has the same value as when the event was created.
So if ID1.value was something when the page was created it will be the same when it is called even if the value of ID1 is different. And that seems to be the case. When I debug the page, before entering the event, ID1.value has the correct value while inside the event it is undefined and after the event it has the correct value. If I write window["ID1"] correct value is also shown.But a weird thing is that in another place in the code I had the same problem but instead of having the code inside the onclick event I first had a global function changeActiveRow and inside that I had an eval, eval(document.getElementById("ID1_script")) where ID1_script is a hidden element whos value is a script using ID1.value and that works.
View 3 Replies
View Related
Nov 23, 2005
I am trying to convert some of my javascripts into a class and am
running into difficulties which i think are related to variable scope.
Basically I have a constructor function for a calendarInput class that
takes 4 parameters, the first is a reference name/number for this
input. I also have some functions for importing my PHP classes into
Javascript using AJAX (properties only. still trying to get methods
working but that's another story!). The relevant function is called
call_object_method(classname, methodname, createparams, methodparams,
post, callbackfunction). This creates an instance of the specified PHP
class using the parameters in createparams. It then calls the
specified method using the parameters in methodparams. The result is
passed back to the javascript function specified in the callbackfunction parameter (ie the value of xmlhttp.onreadystatechange is set to callbackfunction before xmlhttp.send() is called)
The function i am trying to fix is called show (x,y) which creates the
html for the calendarInput and displays it at co-ordinates x, y.
So, my code is as follows:
function calendarInput(calendarid, target, displaytarget, value)
{
this.calendarid = calendarid;
this.target = target;
this.displaytarget = displaytarget;
this.value = value;
this.show = function(x, y)
{
<!--// bunch of init and prepping code. includes creating
createparams and methodparams arrays //-->
call_object_method("cms_calendar", "getcalendarview",
createparams, methodparams, false, this.showcallback);
}
this.showcallback = function()
{
alert(this);
<!--//code to create html//-->
}
}
I know i've cut out most of the innards of this. This is because I
have already tested these functions and had the calendarInput working
outside of a class, hence am pretty sure that this is ok (plus it runs
to almost 1000 lines these days!!). My problem is that when I call the
show method, the alert on the first line of the callback function
returns the function showcallback instead of (as i was expecting) the
instance of the calendarInput object. Whilst this kinda makes sense I
can't figure out how to reference the Object instead. I have tried
'this.parent' but this returned undefined. I have tried changing the
way i reference the callback function (ie the final parameter of
call_object_method) but no joy.
View 2 Replies
View Related
Aug 23, 2010
I've recently started developing javascript using jQuery and so far I'm really enjoying it.Being a professional programmer (mainly C, C++, java and python) there is one thing that's been puzzling me regarding variable scope and unnamed function declarations. Let me exemplify:
------------------------
var sum = 0;
$(xmlobj).find("item").each(function(){
[code]....
View 6 Replies
View Related
Jan 31, 2011
[code]how i can set context/scope for myStartAction so it can access (this.url) variable?console.log(dd.url) will work but i can't predict what name will object have (that depends on user) there might be more than one instance of myObject
View 10 Replies
View Related
Jul 25, 2011
I think the last thing people seem to learn about in JavaScript when they're not coming from other programming languages is variable scope. Some even get all the way into AJAX without having learned about scope, and this is a time when it's really needed. Although the scope of JavaScript variables is non-complex by nature, it's something we should all get a full understanding for before we move too far.
Section 1: What is "scope"?
Section 2: The "var" keyword
Section 3: The "this" keyword
Section 4: Closures or "Anonymous functions and self-invoking closures
View 5 Replies
View Related
Apr 4, 2010
I'm wanting a table cell click event to remove and replace the table it was clicked on, however I'm finding that as it's deleting the original table object the actual running event code is being replaced and the function is bailing.how I can call the delete/refresh function from outside the event's function scope?
View 1 Replies
View Related
Aug 24, 2010
I have a php page in which I declared a js variable... right at the top of the page...
<script type="text/javascript">
var tester = 0;
</script>
[code]....
View 2 Replies
View Related
Sep 8, 2006
I'm trying to access some of the global's inside my class LiveSearch
and I have no idea how to go about it. Here is what I have so far:
<script type="text/javascript" src="query.js"></script>
<script type="text/javascript">
function LiveSearch(global) {
this.theglobal = global;
this.initialize();
}
LiveSearch.prototype.initialize = function() {
$("#thebutton").mousedown(function() { //when we click the button
alert(this.theglobal);
});
}
$(document).ready(function() {
var objSearch = new LiveSearch("globalvalue");
});
</script>
On page load I create a new LiveSearch instance and it assigns
theGlobal = "globalvalue" and proceeds to initialize(); At this point
Im using JQuery to setup an onmousedown event on a button on my page
with id="thebutton". When I click the button the alert comes back with
'undefined'. How can I get direct access to my theglobal variable? Code:
View 1 Replies
View Related
Nov 3, 2010
Not sure if this is possible, but I have an external script that creates an object, and I want to overwrite some of its functionality, but keep the scope.
Here is a basic example:
Code:
<script>
Obj = function (userConfig) {
this._init(userConfig);
[Code]....
I want it to log two Objects, but instead I get two window elements. Is this because I am declaring the functions in the global scope, and not from within the object?
Anyway I can keep the scope of the object, whilst still overwriting the function?
View 2 Replies
View Related
Mar 23, 2010
I am using Ben Alman's JQuery resize plugin in order to obtain the varying computed width of an element when the window is resized (the element in question is a page wrapper that exhibits the expand-to-fit behavior of a block box, and it's computed width is obviously influenced by the resizing of the window. Essentially, what I need to be able to do, is to reference a variable that is defined in a .resize() function ('width_page') in a seperate .each() function.
[Code]...
I now understand that variables can't cross boundaries like in the example above, which leaves me a little stuck. I also understand that this is specific to the context of the .resize() function, and that it can't be taken out of it without using an element selector. Is there some way I can call the .resize() function in my .each() function?
View 3 Replies
View Related
Aug 25, 2006
I am having some fun with javascript, and I came upon a site, on the site you have to try to figure out the passwords which are embedded in javascript, now im on the last level but i have no clue whats going. It seems to be an undefined variable. Can anyone point me in the right direction? Code:
View 1 Replies
View Related
Feb 2, 2011
I wanted to write my own script for a fade-in animation, since the ones I have found have got too many options or need some framework, which makes them unnecessarily big. I wanted to learn too.Unfortunately, the code didn't work as I wanted, and I commented some things so as to find out what's happening.Why is an object reference assigned to what was previously a string?
View 6 Replies
View Related
Jul 23, 2005
Does anyone know why the onclick in the following popup menu gives
the error:"Val is undefined"? Does it have something to do with the
fact that it is called within the variable tablePop? Because it IS
displayed properly as part of the popup text, where it is called
outside the single quotation marks (see [***]). It is only in the
onclick that it's causing problems. Code:
View 10 Replies
View Related
Jul 20, 2005
Any ideas as to how I can get ride of the script error undefined
variable "Exp_Month"?
I am trying to get this drop down list to default to the current month
as opposed to 01.
Thank you in advance.
<SELECT size="1" name="Exp_Month">
<OPTION value="01" selected>1</OPTION>
<OPTION value="02">2</OPTION>
<OPTION value="03">3</OPTION>
<OPTION value="04">4</OPTION>
<OPTION value="05">5</OPTION>
<OPTION value="06">6</OPTION>
<OPTION value="07">7</OPTION>
<OPTION value="08">8</OPTION>
<OPTION value="09">9</OPTION>
<OPTION value="10">10</OPTION>
<OPTION value="11">11</OPTION>
<OPTION value="12">12</OPTION>
</SELECT>
<script type="text/javascript">
var now = new Date()
Exp_Month.selectedIndex = now.getMonth()
</script>
View 10 Replies
View Related
Aug 28, 2009
I code my global variables first, then my window.onload function, like this code...
Why do I get the error:
"KBINPUT IS NOT DEFINED"?
and
Why doesn't the IF statement for UNDEFINED element catch the problem?
View 2 Replies
View Related
Dec 12, 2010
When I click my button, window.frames['akFrame'].document.getElementsByName('auth_key').value is undefined, and I cant seem to make the if else statement work.
<script type='text/javascript'>
url=location.href.split('/')[4];
url=location.href.replace(url,'')
[code]....
View 7 Replies
View Related
Sep 21, 2006
I'm currently coding the beginnings of a stopwatch script.
<html>
<head>
<script type="text/javascript">
var startTime;
var currentTime;
var started = 0;
function startStopwatch() {
if (started == 0) {
var startTime = new Date();
display();
alert(startTime);
}
}
function display() {
currentTime = new Date();
difference = (Number(currentTime) - Number(startTime));
document.stopwatch.display.value = difference;
setTimeout('display()',10)
}
</script>
</head>
<body>
<form name="stopwatch">
<input type="text" name="display" readonly="readonly" size="40">
<input type="button" name="start" value="Start" onclick="startStopwatch();">
<input type="button" name="stop" value="Stop">
<input type="button" name="reset" value="Reset">
</form>
</body>
</html>
The value of startTime when called from display() is undefined. I'm not sure why, as I declared the variable outside the function. The variable should be accessible by all functions, right?
Any help would be appreciated.
View 5 Replies
View Related
