If I have several links with onClick events pointing to the same function, how can I get a reference back to the link that was clicked? I'd like to change the link text after the onClick fires so the user knows something is happening, without having to create and assign id's to every link.
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I've been playing around with JS for a while, but I've not ever found fantastic learning resources. I'm comfortable with other programming languages, so I'm very interested in OOP programming for JS, and I've started to use tools like the Prototype library for that purpose.
However, one problem has consistently caused me problems whenever I'm writing a JS Class. How can I get a reference to the specific class instance from inside an event handler that I create with a class method. Let me give an example of what I want to do:
(This code is using the Prototype library...)
myClass = Class.create();
myClass.prototype = {
makeLink: function(obj) {
// Out here, "this" refers to the instance of the myClass Class
obj.innerHTML = ''
obj.onclick = function() {
// In here, "this" refers to the clicked on element.
// How do I get a reference to the instance of myClass in here?
}
}
Here's the best way that I know how to do this right now. It seems to work in Firefox alright, but doesn't seem to work in IE:
myClass = Class.create();
myClass.prototype = {
makeLink: function(obj) {
obj.innerHTML = ''
self = this; // Save a reference to class instance as "self"
obj.onclick = function() {
// Self is evaluated to instance reference at time of assignment to onclick
self.linkClicked();
}
linkClicked: function() {
// Do something useful here
}
}
Is there a more elegant way to do this? I could just create all of my event handlers for objects outside of the class in procedural code where I already have a reference to the class object, but I like to wrap these things up inside the class, because sometimes they get significantly more complicated than this very simple one. Anybody have any solutions? This has to be a common design pattern...
I am using following JavaScript code to add click event on anchor tags with attribute rel="gcode"
Now I need a script to highlight all anchor tags which have an click event attached with them.
Is it possible using JavaScript to get a list of events attached with an object? Also I will need to check the code used in every event. (It is something like an Quality Assurance or Debugging code.)
Code JavaScript:
function gLinks() {
if (!document.getElementsByTagName) return;
var anchors = document.getElementsByTagName("a");
for (var i=0; i<anchors.length; i++) {
[Code].....
I am creating JS objects that have some properties that contain DOM nodes, and some of these DOM nodes have event listeners attached to them. When I delete such objects, do I first need to remove the event listeners attached to some of the DOM nodes? And do I need to use removeChild on the DOM nodes that are properties of the object? Or does JavaScript take care of all that?
View 1 Replies View Relatedi am working on a custom drop down list that has hidden #options DIV which is shown when the user clicks on a button. the problem i am having is that the click event does not seem to be attached to the LI elements since they are hidden when the page first loads. if i show the #options DIV when the page loads everything is working as expected.i've tried to attach the click event after i show the hidden UL but that didn't work either.what can i do to make sure the LI click event fires? i tried to put A tag inside of LI and attach click to that but to no avail.
<style type="text/css">
.gbtn-options {
overflow-y:auto;[code]....
I know just enough javascript to be dangerous, I created a 5 star rater for pages, which is set up something like this:
Code:
var starRater=function(id){
// get latest rating info from server, write into "id" div, etc
}
//later in code...
var rating=new starRater("rating");
Over the course of development I added a comment section, page visit count and so forth, and ended up with redundant code and a lot of calls to the server. I thought instead I would make one initial call and then initialize the elements with the information returned.
To be able to call the initialize function on these elements, I need some reference to them. I could call them directly, as in the example above I could call rating.init(), but I'd have to know what variable name was given to it. Instead I was thinking I'd pass some sort of reference to the object, but that doesn't seem to be working.
[Code]...
In the code above I get undefined for raterElem.testVar. Obviously I'm missing something. What am I doing wrong?
I have a Class name Merkzettel.
[Code]...
and addClickEvent sets the onclick attribute of above mentioned DIV. and in addClickEvent I am explicitely mentioning the name of class object. This means every time I create a Variable with another name I have to Change this function also.
My question is commented in the script:
function Love(){
var req = {
ring : 'gold',
[Code]...
console.log(details.ring); // why does this return gold and not silver if req is passed by reference and we already changed its value above and so it's pointing to the same memory position?
This works in firefox:
document.eval(formname).elements.length
it does not work in any other browser
I call the same elements tag in lots of places, I'd have to wrap a large chunk of code in eval to make it work in other browsers. Is there any other way to call a dynamic object name?
$(function(){
$('.table_pay').dblclick(function(){
if($('div', this).is('.value')){
[code]...
What to do on the 13th line that the reference object which is on the 2nd line (the class named"table_pay") will be its reference call..
Is it possible to get a reference to a form's document object exclusively from a reference to the same form? I mean, for example, if I have:
var f1 = document.forms["form1"];
var f2 = parent.document.forms["form2"];
var f3 = top.document.forms["form3"];
Is it possible to get the document object of each form only from these vars? Is there something like, i.e., a "form.document" property?
I have an error when I try to make:
CustomObj =
{
is_all : Compatible(),
Types :
{
PASS : CustomObj.as_all ? "ok" : "onok",
...
...
...
but in an object literal notation I cannot use a parent object
variable? or
can I do to create a global variable inside my parent class
(CustomObj) and
than to use in my children objects like Types?
The goal is for selectedDay to be assigned the value of the system variable Mainpackage.subclass0.subclass1.firstDay and then incremented by two days. Mainpackage.subclass0.subclass1.firstDay needs to be unchanged.
Important system variable in red. To be 'manipulated and used' variable in green. Even with an intermediary, third, dummy variable it doesn't work:
Console log is:
It doesn't work in my webapp : All variables change at the same time.
I am fairly new to JavaScript, have been using VBscript before and JavaScript comes off a bit illogic...
Anyways, here's what I am trying to do:
function TestFileType(formname) {
fileName=document.[formname].img1.value;
apparently I can't reference a form object like this. What is the correct way of going about it?
I have searched the web and this forum for the answer to this but am unable to find a reasonable choice. So, this is the problem I am facing.
Code:
var str = "document.frames[0].document.frames[0]";
var str 1 = "document.frames[6]";
//Loop Starts
{
var obj1 = str + str1;
[Code]...
I know the easiest way to do this is to use eval() and it most definitely does work. The problem is that I have to use eval() inside a loop to check whether the reference is null and from what I hear, that is one of the most inefficient ways to code. I have searched for alternatives like using, var myFunc = new Function(string) and then calling myFunc(). But this does not work in my case. I cannot find any other alternative in this case. I guess one can say eval() is the only choice here but I am not too sure.
I have a function that changes the innerHTML of a DIV element. I want to pass to that function as a parameter a reference to the DIV to be changed. In the example below it works the first time (executed with the body onLoad event). As the subsequent function declaraton is rewritten by the function itself, it can no longer reference the targeted DIV. I tried to pass a string teference and use eval(), but this time it fails the third time it is executed.
Code:
<html>
<head>
<title>Passing Parameters to a Function (with object prameter)</title>
<script type="text/javascript">
[Code].....
For a site, I am making a listing object. What it does, is it fetches rows of data from a serve using JSON. The object has a method called loadlist.to print out the data it now does something like this:
str="";
$.each(jsondata,function(){
str+="<tr>";
[code]....
I have just started using the data functions in jQuery for keeping track of a few items on the client. The user can click on links, which call a function that updates the display and stored data value.I am storing data as a set of columns, named c1, c2, c3 etc.
I update the relevant column like this
function UpdateCol(column)
{
[code]....
How do I store an object reference inside a variable when I want the object reference to to reference the first "ul" html element nested inside the current object (as referenced by this keyword)?
var slideList = ???
I am trying to create a sliding menu.
I simply need to reference an object inside an iframe:
I need it to work on all browsers as I understand this is difficult for this type of command.
Why does the below code not work in ANY browser let alone all of them.
I have tested in IE8 and FF3 (not IE7).
file1.html
---------
<iframe name="iframe1" id="iframe1" src="file2.html"></iframe>
<script>
parent.iframe1.form1.obj1.disabled=false;
[Code].....
As far as readability and consistency, which is better in your opinion (or if functional difference, that I didn't account for,)
Event.observe($('txtName'), 'keypress', handleKeyPress);
Choose one:
A.
Code:
function handleKeyPress(event) {
alert(event.keyCode);
}
B.
Code:
function handleKeyPress(evt) {
evt = evt || window.event;
alert(evt.keyCode);
}
C.
Code:
function handleKeyPress(evt) {
evt = evt ? evt : window.event;
alert(evt.keyCode);
}
I would like to know how to pass in a reference of this to anonymous function so I can access parameters from anonymous. Here is my code:
[Code]...
I am confused about what the return keyword is actually returning when returning an object, a primitive, or a function. My confusion is compounded by the fact that I'm not sure if a function is an object or not. According to the book JavaScript Programmer Reference it is: "All functions in JavaScript are first class objects , meaning they can be passed around like any other object reference. In fact, regardless of how they are created, functions are instances of a global object named (aptly) Function."
However, someone else states that a function is not an object. An object is a set of primitives and references. A function is executable code. Functions become objects through the use of the new operator. Yet, in the book I mentioned, it says you don't need the new keyword to execute the function as an object, as it already inherits from the object Function when the function keyword is used:
function functionName([argname1 [, ...[, argnameN]]])
{
statements;
}
So there's one source of contradiction. Now the bigger issue is what is going on when the return keyword is used. Notice the Validation() function returns an object as its last expression. This technique is common, where you return an object which contains functions in form of object notation. I believe this is done so that we create a closure so that when the intepreter exits the Validation() method, since we created a closure by returning an object, which contains the inner functions addRule and getRule, the local variables of Validation() are not destroyed, given that we can reference them through the two inner functions that make use of the local variables of the outer function. So when we use the return keyword on an object literal, and then exit the function, when we call one of the inner functions as we do later:
[Code]....
I'm new to jQuery and Javascript overall, I have searched the internet to make use of jQuery instead of the HTML's iframe tag. My problem is links inside a .load file, I want them to refresh the box on the index.php file, not the file itself (in this case the links are in blog.php)
Here's everything I can provide with:
Files:
"index.php"
"blog.php"
In my index.php file I have this script to make my index.php links open the required file in my div box.
"index.php"
<script language="javascript" type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#html").load("blog.php"); // shows the blog.php when I first enter index.php, which I want to have
$(".link_click").click(function(){
$("#html").load($(this).attr("id"));
});
});
</script>
Here's "index.php" link:
<a class="link_click" id="blog.php">Blog</a>
Here's my div box in "index.php" where I show the information within the loaded file:
<div id="html"></div>
All this works, but here's my problem, I have multiple links within "blog.php" which I want to make "index.php" to refresh the "index.php"'s html div. Is there some kind of way to edit the "blog.php"'s script to make it "index.php" the parent or reference?
"blog.php"
<script type="text/javascript">
$(document).ready(function(){
$(".link_click").click(function(){
$("#html").load($(this).attr("id"));
// Need to change this(?) to make it reference the index.php's html div box
});
});
</script>
how can I detect if mouse cursor is over or out of some element? I am running a animation, which I don't want to run or to stop itself if cursor gets to area.
View 3 Replies View RelatedI'm wondering if there is a way to identify the "current" tag or the tag within which an event is triggered as a reference point in a javascript function.
Thus, can I set up a function so that when a certain tag is clicked it will do something to, say, the child of the tag that was clicked?
The function would say "do something to the child of the tag that triggered the event by being clicked."
I know I can do this by identifying the tag by ID, class or some DOM location. What I want to know is if I can can identify it by the fact that it is where the event was triggered.
