I'm creating my first javascript OO application. I'm running into a problem with prototypes.
function Control(Name)
{
this.Name = Name
}
Control.prototype.SayName = function ()
{
alert(this.Name);
}
When I call SayName (), this.Name is undefined.
I know I shouldn't be having this problem at this stage. But what have I done wrong?I have my main page, I have my onload page and in that onload page I call a function:And then I get the error message:Fatal error: Call to undefined function OpenChat.Needless to say I am trying to create an instant chat.
View 26 Replies View RelatedI'm getting the following error when i try to get the next sibling of the current node in php:
Fatal error: Call to undefined method DOMElement::next_sibling() in C:wampwwwAjaxgetcd.php on line 1
cd_catalog.xml
<CATALOG>
<CD>
<TITLE>Empire Burlesque</TITLE>
[code]....
According to ECMAScript, the root of the prototype chain is Object.Prototype. Each object has an internal property [[Prototype]] that could be another object or NULL.... However, it also says that every function has the Function prototype object: Function.Prototype, it confused me, because a function is an object, for a function object, what is its function prototype and object prototype..For example:
var x = function (n) {return n+1;};
what is the relationships of x, Object.Prototype and Function.Prototype
I am trying to get to the bottom of javascript object, prototypes etc. I have a fairly good grasp of it, but I get confused the closer I get to the base object.prototype. FIrst of all, I was under the impression that all objects descend directly from Object. But some objects (like Array) seem to inherit properties and methods from the function.prototype. So does this mean that the chain is like this:
object -- function -- array Second, I noticed (on the mozilla javascript reference site that object.prototype inherits properties and methods from function.prototype and vice versa!? How can this be? I must be missing something important about understanding the chain?
is there a way in jQuery to bind variables to function calls similar as prototype.js does it? See [URL]
E.g. in the slideUp method of jQuery you can specify a callback that is called after the effect has finished. I would like to bind a variable to this call so that it is used inside of this callback as a closure.
I would like to call a function within a function. When I do this I get "undefined"
Here's my code:
<html>
<head>
<script type="text/javascript">
function product(a,b){
[Code].....
I know you can just return in the first function, "product()" but I would like to do something else in my second function "display()" then return a value.
I need to make a $.post call on the beforeSend event of another $.ajax call.I read the documentation and I see that if the beforeSend return false the ajax call will be interrupt.So I made this code but doesn't work, because the real value of the beforesend function isn't true or false, is the value of the post.I have to do this because when you click on a link I need to verify before if you are able to do this via db permission of my webapp.I think you don't understand...This is the code:
$.ajax({
async: true,
beforeSend: function(){[code]....
});I see always the alert of success event, so the return of the beforesend is not correctly done.
The general framework is a simple user login function. The user name is selected and a password entered as usual. The function grabs the element values and passes them to a php page that queries the database. An AJAX call returns the password to the function and then I want the innerHTML to be a choice of two web pages, depending on success or failure of validation. There are existing AJAX functions available on the internet but they are overly complicated for what I think should be a simple, quick to load function.
Where I am stuck is that the standard procedure to make an AJAX call is the browser window event. How do you make the call from within the function? I have tried creating two new variables, "success" and "again" to replace xmlhttp, but still stumble on the event to assign a value. I left the blank password protection (if statement) with that variable to demonstrate what I mean.
I've put in my code below, which is in development and successfully alters the innerHTML text depending on user input but I can't figure out how to insert the relevant php page. I have '// out' the testing bits, but left them for info. (I have tried full 'scripting' as the innerHTML, but it's messy.)
I can use "with" like this:
function MyObject(message)
{
this.message = message;
}
function _MyObject_speak()
{
alert(this.message);
}
with (MyObject)
{
prototype.speak = _MyObject_speak;
}
I was wondering why I can't use "with" like this:
with (MyObject.prototype)
{
speak = _MyObject_speak;
}
One of the complaints about prototype.js (google for it if you're not
familiar with it) is that it's poorly documented. I have this inkling
that the key to understanding prototype.js is in the bind function.
The problem with Javascript is that the "this" operator is poorly
overloaded and it is often hard to understand in the context of
object-oriented javascript
So, let's start with the definition:
Function.prototype.bind = function(object) {
var method = this;
return function() {
method.apply(object, arguments);
}
}
As I read this, it states that all functions (which are themselves
objects) will, in the future, have an associated method called "bind".
The function() function, so to speak, simply instantiates a Function
object with the parameter list and then evals the statement, sticking
the resulting execution-tree in the current code frame.
The "this" there refers to the function object associated with the call
to bind(), right? But the word "arguments" there refers to the
arguments passed to the function object *generated by* the call to
bind().
In every example within prototype.js, bind() is called either in a
constructor or within a method contexted to a javascript object, and is
always called with "this" as its argument, e.g.:
this.options.onComplete = this.updateContent.bind(this);
As I read the code it seems to be stating that the "this" object
referred to within bind()'d functions are being coerced into always
referring to the current instantiated object.
But isn't this always the case anyway? Is this a rather confusing
attempt to ensure "this" purity whereby the call
method.apply(object, arguments)
is forced to always have the reference to the containing object present?
I think I've got it. Bind() generates uniq functions that contain live
references to the objects to which they belong, such that the function
object can then be passed to setTimeout() or onMouseOver(), handlers
that accept functions but not objects.
Lets say we run: window.alert = function() { };
Is there anyway to 'restore' the original alert() method or is it gone
forever?
I know you can do window.alert = Window.prototype.alert, but lets say
you also set Window.prototype.alert = function() { } or lets say we're
in Opera, which doesnt have a Window "class".
I would like to set up an event observer outside of an object, so I
can't use this.bindAsEventListener. How can I pass the correct object
reference?
I tried something like this, and various other variations, but no luck.
This works when I set it up from inside the object, using "this.",
Event.observe(targetId,'click',targetId.select.bin dAsEventListener(this),false);
I wanted to add an object as a prototype to separate my methods more
nicely, however, I ran into a couple of problems. Apart from the
obvious "scope" issues I found that any instances of my class shared
the objects methods and properties.
I realise (now) that this is actually how prototypes work, they share
functions and objects rather than create new instances of them for
every "class", but is there any way around it? (or shouldn't I be doing
things like this at all?) Code:
I am working on my own pop up calendar, mainly because the one I am currently using crashes the Safari browser at times.
So, I want to verify that what I am doing will work, in that I want to be able to have multiple calendars open at the same time, each independent of the other.
So, I start it off with:
var Calendar = {
dateSelected: null,
topPos:null,
leftPos:null,
somefunction:function(e) {
...
}
};
If I create more than one calendar object, will they have their own variables, in that the dateSelected, topPos and leftPos will be unique to that instance?
Or, is there a better way to do this, that is cross-platform.....
In my research in the javascript language I have encountered problems
with implementing prototype inheritance while preserving private
methods functioning properly. Here is an example: Code:
I want ask you if, for a web portal/application, is better prototype or Jquery? I don't want to innesc some type of flame, but after the announce that drupal use JQuery and that the new Wordpress
2.2 use Jquery I ask myself if my choice of use prototype.js is the bettere choice.
I have <div id ="changeable"> with some html in it. I have a link that calls the function to replace the info in the div. The problem is that the "creative_development.inc" file is added to the top of the div and does not replace the content. How do I replace the content, and not just add content?
View 1 Replies View RelatedI'm trying to make an addEvent function that will automatically attach itself to the object using a class.
My question is how can I add the function so when I write obj.addEvent("click",myfunction); it will add the event?
Here's my current function:
this.prototype.addEvent = function(type,fn)
{
if(window.attachEvent)
this.attachEvent("on"+type,fn);
else if(window.addEventListener)
this.addEventListener(type,fn,false);
}
I need help to workaround the following problem:
First, about the environment:
- The web pages automatically generated.
- Pages can be inserted to each other
- When a subpage to be inserted is being generated, it does not know will it be inserted or not.
- That because each subpage uses the <script src=...> tags to load the script it needs.
- in the external script files I'm trying to protect it from repeated execution checking (if(){}) the value of a variable which is created after in the script.
Everything worked fine until I tried to use the .prototype to declare the method of my objects.
In the Internet Explorer, I got "Object does not support this property or method", on the access to a prototype function, because the prototype of my object was deleted by itself after the second load of the external script. Code:
This function will return an array of the elements in a page that contain a certain attribute, you can also give it a value that the attribute has to match, a tag name that the element has to match and a parent element.
I know there are other functions for doing this, but this one is written for use with the prototype (http://prototype.conio.net/) JavaScript library, in fact its really just a modified version of the getElementsByClassName() function that’s part of prototype.
document.getElementsByAttribute = function(attribute, value, tagName, parentElement) {
var children = ($(parentElement) || document.body).getElementsByTagName((tagName || '*'));
return $A(children).inject([], function(elements, child) {
var attributeValue = child.getAttribute(attribute);
if(attributeValue != null) {
if(!value || attributeValue == value) {
elements.push(child);
}
}
return elements;
});
}
Usage is pretty simple, this will return all elements with a width attribute:
I try to get a xml-response with prototype. for e.g. i have the following code:
<html>
<head>
<title>Test Ajax</title>
<script src="prototype-1.3.1.js" type="text/javascript"></script>
<script type="text/javascript">
//<![CDATA[
var getXML = function()
{
var myAjax = new Ajax.Request(
"bsp.xml",
{
method:'GET',
onComplete:showXML
}
);
}
var showXML = function(r)
{
var names = [];
var root = r.responseXML.getElementsByTagName('personal').item(0);
// root
for (var i = 0; i < root.childNodes.length; i++)
{
var node = root.childNodes.item(i); // mitarbeiter
names.push(node.childNodes.item(1).firstChild.data);
}
$('xml').innerHTML = names.join("<br />");
}
//]]>
</script>
</head>
<body>
<p>
<a href="#" onclick="getXML();return false;">TEST</a>
</p>
<div id="xml">
</div>
</body>
</html>
xml-Data:
<?xml version="1.0" ?>
<personal>
<mitarbeiter>
<vorname>John</vorname>
<name>Brown</name>
</mitarbeiter>
<mitarbeiter>
<vorname>Matt</vorname>
<name>Blue</name>
</mitarbeiter>
</personal>
This works fine in IE but in Geko-Browser i got nothing back, because this browsers build the DOM with linebreaks and whitespace. Do you have any ideas what is wrong in my code and how to get propper DOM?
Having read through Sergio Pereira's Prototype documentation I came across the grep command within Enumerable object.
This is something that looks very interesting. Such as being able to quickly select only the elements you want using a regular expression.
But for the life in me I can seem to get it to work.
Anyone a bit more up to speed with Prototype care to have a look?
var elementList = Form.getElements("just-a-form");
nodes = $A(elementList);
var localElements = nodes.grep( /image/, function(node){
return node.id
});
I'm using Prototype's AJAX to get the "alert" the response of a simple PHP script (a script that echoes a single line), but it doesn't seem to work. Here's the code:
function init()
{
var url = "http://localhost/script.php";
var myAjax = new Ajax.Request(
url,
{
onSuccess: showResponse
});
}
function showResponse(response)
{
alert(response.responseText);
}
window.onload = init;
The code has no errors, but still doesn't show the response even if i add an onFailure event handler. What could be wrong?
OK, simple script that currently takes an array of ID values (hard coded) and then iterates through them to fade in and out creating a slideshow.
The obvious problem is I have to hard code the number of DIVs in the slideshow. What I really want is the code to get the child elements of the container I pass it and then iterate through them dynamically.
[Code]...
I am trying to use the sortBy function in the prototype.js
library. Nevertheless, I can't work out what to include in the iterator
function. Can someone shed some light on this?