I have static object and I want remake it to a constructor with property 'length' which would be not enumerable in for loop... This is my object and how I generate it
[Code]...
I had read from books that the constructor property of object is inherited from its prototype. And the prototype can be changed dynamically. New property can be added to or deleted from object even it was created before the prototype change.
But I got confused on below codes.
But the actual result (both IE and firefox) is
Trying to add a new property to a non-jQuery object from inside each loop doesn't appear to work:
var arguments=new Object();
arguments['ticket']=ticket;
arguments['email']=email;
arguments['module']=module;
arguments['epoch']=new Date().getTime();
var total=0;
$('select.category').each(function(){
var name=$(this).attr('id');
var option=$(this).find('option:selected').val();
total+=parseInt(option);
arguments[name]=option;
});
The 'total' variable works as expected. The the 'arguments' variable doesn't. Almost like
a variable scope issue or something. If I put some extra debug code to print out all the
property/value pairs, outside each loop I only see original four, and inside each loop only
the new one just set and none of the original four.?
What happens if you do this?
function Person() {}
Person.prototype = 7;
var ted = new Person();
Also what happens if you set Person.prototype to an array or function?
How would I go about copying all the prototype functions AND the constructor from one object into another object, and then call them?
I know I can use this.example.call(this), but that's not an acceptable solution. I want to deploy this style over dozens, potentially hundreds of objects.
I need to detect the "name" of the constructor of an object. For example, myArray.constructor === Array is true, but I want something where that === 'Array' is true. I've heard of Object.constructor.name, but it's not widely compatible. (preferably without involving regular expressions)?
View 4 Replies View RelatedI am trying to understand why I had an error, or why my solution worked. In my HTML I had:
<script language="JavaScript" type="text/javascript" src="Book.js"></script>
<script language="JavaScript" type="text/javascript" src="Book_TEST.js"></script>
Book.js said:
[Code]....
Now, the code worked fine in both script. (i.e., no more error.) So far as I can tell, the only differences between the first and next version of Book.js are the comments and the whitespace. Am I missing something? Can the comments or whitespace somehow effect the logic with which this code has been executing? If I get an error like this again, is there an easier/better way to fix it than to essentially retype the code?
How to extend the constructor for the date object of the javasccript so that whenever a call is made to the constructor, I want to perform a particular action? Basically how to define wrappers for default javascript methods or objects like Date() so that I can perform some action and then invoke the original method? So basically if I have something like var a = new Date(); I want it to (say) alert the value of the date everything Date() is called and then execute the default date constructor.
View 3 Replies View RelatedI have a requirement to override the constructor of a javascript class. I have to execute the current constructor code and then call a javascript method. Basically, I need to execute a javascript method whenever an object of that particular class is created in addition to whatever is being done now. I do not want to copy and paste the current constructor code and override the initcomponent method. I am looking for an alternative for that.
View 5 Replies View RelatedI need to create a constructor for a computer object. This object must have three properties: speed, and mem_live mem_dead. Then I need to create a new object using this constructor and then have its properties displayed on the screen.Look at what I'm up to so far:
function Computer(speed, mem_live, mem_dead)
{
this.speed = speed;
[code]....
It always just shows : 4.0ghz, true, false
function show() {
var s = '' ;
for (var i = 0; i<arguments.length; s += '
'+arguments[i++]) ;
typeof(window) != 'undefined' ? window.alert(s) : WScript.Echo(s) ;
}
function f(){}
show('delete(f):',delete(f)) ; // false
g = function(){} ;
h = new g() ;
show('h:',h) ; // [object Object]
show('delete(g):',delete(g)) ; // true
show('h.constructor:',h.constructor) ; // function(){}
show('delete(h.constructor):',delete(h.constructor )) ; // true
show('h.constructor:',h.constructor) ; // function(){}
is there a delete for a object inside the constructor, while i init it?
i will try something like that:
var obj = function(a)
{
if (!a) delete this;
this.a = a;
}
Sorry, bad title. Anyway, is there a way to pass the arguments to an object
instantiated via a constructor using the arguments object and have it
expanded, so to speak, so that it doesn't appear as a single argument? I'm
sorry, this explanation is just atrocious, but I can't think of exactly how
to word it. Maybe an example...
Take for instance Function.apply. It takes 1-2 arguments, the first being
the object to use as the context, and the second being either an array or an
instance of the arguments object which are to be the arguments for the
function. I want to do something similar but I want to also basically use
the new operator so that I get back an object.
Here's a snippet of some of my code, maybe this will help:
I'm sure this question has been asked many times before, but I can't seem to get the correct terms to find the answer in Google.I understand basic JavaScript inheritance. However, everything I've read makes the inheritance work something like this:
Code JavaScript:
var ChildClass = new Function();
ChildClass.prototype = new ParentClass();
ChildClass.constructor = ChildClass;
That's fine, but what happens when ParentClass's constructor needs parameters?As an example, look at the following code:
Code JavaScript:
function Furniture(color){
this.color = color;[code)....
How could I "copy" Furniture's constructor into the Chair object? Better yet, how could I copy Furniture's constructor and then add some functionality to it?
I have a code set up something like this:
[Code]....
The problem is I keep getting an error along the lines of: TypeError: Result of expression 'house' [[object Object]] is not a constructor. It seemed to work when I wasn't passing the other objects as parameters in the constructor. I just created and assigned them later. As in:
[Code]...
I'd like to make a Degree object that inherits from the Number object and uses the Number constructor but adds a .rad() method that returns the value in radians.
If I do something like:
It generally works but I don't get Number's methods like toString and toPrecision.
I need a java bookmarklet that does a real simple thing. I need to take the current URL (ie, where the user is when they click the bookmarklet) and append it to a static URL and return the text on the resulting page.For example:
The user is at http:[url]....
The user clicks the bookmarklet.
the bookmarklet takes http:[url].... and appends it to http:[url]... HERE where you see the URL HERE text.That PHP script echos a simple line of text (a shortened URL actually).Then I want that result from the outside_create.php file to be displayed in a window back to the user.Is this even possible? Basically I need to know how to append location.href to a static URL and how to get the resulting content from the static URL..
I've recently been following the object-oriented techiques discussed
here and have been testing them for use in a web application. There is
problem that I'd like to discuss with you experts.
I would like to produce Javascript classes that can be "subclassed"
with certain behaviors defined at subclass time. There are plenty of
ways to do this through prototyping and other techniques, but these
behaviors need to be static and protected. By protected this means
that they can be overridden (or reassigned) in subclasses, and
privileged subclass methods can access them, but callers external to
the class cannot.
I've been attempting to define a factory function that transfers its
parameters to an anonymous object while defining the constructor in a
-with- block. (This is what I'm loosely referring to as "subclassing"
- it's really object composition.) This works, but not for
externally-defined functions. They can't see the protected static
members....
I have an object with a single Method to load content from a xml file. The problem is... how do I add a property to the object to store the data loaded?? I tryed adding a simple Array inside the object, but didn't work.
[Code]...
I am running a bit of JS to highlight text inputs onFocus in IE. It
seems to be working on all of the forms on the site except one. The
debug code in the script displays the number of input elements in an
alert. On the page where it does not work, the alert is "[object]".
Here is the script:
function initHighlight() {
if (!document.getElementsByTagName){ return; }
var allfields = document.getElementsByTagName("input");
alert (allfields.length); // debug
for (var i=0; i<allfields.length; i++){
var field = allfields[i];
var attr = field.getAttribute("type");
if (attr == "text" || attr == "password") {
field.onfocus = function () {
this.className = 'highlightActiveField'
}
field.onblur = function () {this.className =
'highlightInactiveField'}
}
}
}
function addLoadEvent(func)
{
var oldonload = window.onload;
if (typeof window.onload != 'function'){ window.onload = func; }
else { window.onload = function() { oldonload(); func(); } }
}
var isIE = navigator.appName.indexOf("Microsoft") != -1;
if (isIE) { addLoadEvent(initHighlight); }
Unfortunately, I cannot reveal the URL of the page (contractural
restrictions).
Under what conditions would IE believe that the length of input fields
is an object, not a number? I have run the page through two
different validators and there are no errors.
I have the following JS load up via file in the headers of my HTML[code]...
No matter how many times I run the function, it returns 0 for the first two alerts. The first time I run it, it should output "1", then "3". The next time should be "2", "3". Am I instantiating/populating the JS arrays incorrectly? Been working on this for 2 hours, shouldn't be taking this long
The function below results in this error and I'm not sure how to correct it? The initial value of the field is 0.00, but it doesn't look like it's relevant.. That is, even when the value isn't 0, it still results in this error.
Code:
if($("input[name='b2h']")) {
$("input[name='b1']").bind("keyup", b2);
b2();
}
[Code].....
I have added an validation script for Pizza menu. Validation working fine in all browsers except IE. When I working in IE8 it throws an error "length is null or not an object error in IE8". See Java script code below:
<script>
function UnCheckRadios(radioButtonGroupName)
{
var formName = "frmOrder";
[Code].....
The function below results in this error and I'm not sure how to correct it? The initial value of the field is 0.00, but it doesn't look like it's relevant... That is, even when the value isn't 0, it still results in this error.
if($("input[name='b2h']")) {
$("input[name='b1']").bind("keyup", b2);
b2();
[code]....
I started getting a wierd problem with my jscript program. Here im using jscript for client-side validation and upon email field submission,im getting undefined value with an error saying "length is null or not an object". All the values of fields prior to that are being obtained properly.
View 6 Replies View Related({}["toString"]) - function
alert("toString" in {}) - true
But I want to only find a property that is defined in the object - not in a prototype.
for(var prop in {}) { alert(prop); }; // toString not found.
It seems that operator 'in' is overloaded. 'in' during iteration: look in the property. 'in' in a boolean conditional: look in the object, then up the prototype chain.
I want a way to get only properties defined within the object itself, not it's prototype. Is there no simple way?