jQuery: window.opener makes a difference - javascript

I'm working on localhost (so would expect to not have any domain-related probs as here).
On a page I'm using a bit of JS to modify the content of a span in the opening-window. It does not work.
When checking my code to find the control, it works (using FF dev-tools calling my Increment-function or checking the console.log-output): $('#uploads_Count')returns an object of type HTMLSpanElement. However, trying to access the same control from an opened window's console with window.opener.$('#uploads_Count'), this returns an HTML-Document, seemingly the entire page. Why is this not working, what am I missing here?
Here is function that is supposed to increment the counter contained in the span whose id is given as argument:
function Increment(ctrl)
{
var gef = $("#" + ctrl);
if (!gef) // did not find control, maybe on opener?
{
gef = window.opener.$("#" + ctrl);
}
console.log(gef);
cnt = parseInt(gef.text() , 10);
cnt++;
gef.text(cnt);
}
The HTML is trivial:
<span id="uploads_Count">0</span>

If $(selector) returns an element (such as HTMLSpanElement), rather than a collection of elements (would look like [<span id="uploads_Count"></span>] in most dev tools), then you're not calling jQuery.
Dev tools in A-grade browsers tend to introduce $ as a selector function. It is available in the developer console only.
If window.jQuery exists, then it's likely that jQuery.noConflict() was called, in which case you should use window.opener.jQuery.

Found it!
The way I checked if the control was found, was wrong. Instead of if (!gef)I should have used if (!gef.length). Found the explanation here.

Related

javascript create object with attributes using getElementById

I've built a simple practice game with 5 values stored separately. I want to put these 5 values/divs into a single object, but I'm confused about the output. the console.log returns: "the value for cardValue is [object HTMLDivElement]". The first part is working, but I'm confused about the latter. When I type into my console player.cardValue I get 'player is not defined'. Any help is appreciated. Thanks.
var cardValue = document.getElementById('cardValue');
var cardValue2 = document.getElementById('cardValue2');
var playerHit1Div = document.getElementById('playerHit1Div');
var playerHit2Div = document.getElementById('playerHit2Div');
var playerHit3Div = document.getElementById('playerHit3Div');
var player = {
cardValue: document.getElementById('cardValue'),
cardValue2: document.getElementById('cardValue2'),
playerHit1Div: document.getElementById('playerHit1Div'),
playerHit2Div: document.getElementById('playerHit2Div'),
playerHit3Div: document.getElementById('playerHit3Div')
};
for (var x in player){
console.log('the value for ' + x + ' is ' + player[x]);
}
You seem to be confused about the behaviour of the console. It's implementation dependent and has quite different behaviour in each browser that has one, so you need to learn the peculiarities of the one(s) you are using.
Running your code and entering player.cardValue into the console in IE returns:
player.cardValue
null
In Chrome it returns:
null
Which is expected as I don't have any element with an ID of cardValue. Note that if you do have suitable elements in the page, they must be before the code, otherwise when the code runs, the elements don't exist yet. Or you can run the code after the onload event (e.g. use window.onload = function(){...})
If you wish to get the text content of an element, then use its textContent property. Older IE supports innerText instead, so you can do:
var theText = element.textContent || element.innerText;
If you want to get the markup inside the element, use its innerHTML property, which has been supported by all browsers for a long time:
var theMarkup = element.innerHTML;
To see reliable output, write your own output routines and don't rely on the console's interpretation of what you might want, at least until you are familiar with how they work.
I think that console log has many cool features like error / debug / warn / info / assert, you can also profile and also trace. console.log has very cool features and is browser dependent as it was spoken in the comments.
If there is an element in DOM with id cardValue you will get in player.cardValue the Html Object that represents it, you will actually get the value or text of the DOM element depending on the kind of element it is.
For instance getting the text from an element could be some times innerText of the element and in other cases .value attribute of an input text and so on.
Accessing to those values depends on each case of the element you are trying to get info from. And not only that but actually also depends on the DOCTYPE you define, so it is good to have some kind of library to get access in the correct way to the values we need from DOM in the way we expect.
I will also add a reference a book I read, that explains that accessing with attr of jquery actually handles browser incompatibilities.

Can't access object in jquery (prevObject?)

A function in my WP plugin has just randomly (as far as I can tell) stopped working.
Here's the code in question:
window.send_to_editor = function(html) {
var classes = jQuery('img',html).attr('class');
var items = classes.split(" ");
... more stuff here
}
I've confirmed that the html variable is indeed an img html tag. Here's what firebug shows when I do a console.log of the object (console.log(jQuery('img',html));):
Object[]
context -> undefined
jquery -> "1.11.2"
length -> 0
prevObject -> Object[img.alignnone.size-full.wp-image-1234 name.jpg]
And the error it shows is classes is undefined.
I figure there's something wrong with the object I get, but this used to work recently and I'm not aware of any changes in the site that could have caused this.
I'd appreciate any input on this.
EDIT:
More info. This happens with two plugins which are supposed to be unrelated (made by different people). It happens when, after uploading an image to the server (or selecting a previously uploaded picture) you try to insert it into the post.
As I said before this error has appeared out of nowhere, it was working as intended a couple days ago. The only thing I can think of that has changed since then is the domain name, but I can't see how that could be related.
The jQuery selector always returns a jQuery object, but when the length is 0 then no elements were found matching the selector that you provided. In your example you've confirmed that nothing is selected as the length of the jQuery object is 0. Perform a check whether an element was selected like this:
var $els = jQuery('img',html),
classes;
if ($els.length) {
classes = $els.attr("class");
}
Keep in mind that your DOM query is limited by what you pass in as the html parameter. If you simply want to find the images on the page do: var $els = jQuery('img');
I finally managed to fix this; the key was parsing the html string variable into proper HTML, using jQuery.parseHTML(). Thanks to everyone who helped!

Reasons a variable can be undefined on iPad vs. being defined in my Browser?

I'm clueless.
In my Jquery Mobile Plugin I'm declaring:
var $currentEntry = $.mobile.urlHistory.stack[$.mobile.urlHistory.activeIndex].url;
$activePage = $('div:jqmData(url="'+ $currentEntry +'")');
So I'm taking the active page's url and use it to construct an $activePage object.
This works fine on desktop, but on my iPad (iOS3.3), $currentEntry is defined correctly, but $activePage is undefined.
Question:
What can be reasons for this?
You can rule out race conditions, because wrapping this in a 10sec timeout still produces the same result. Also, if I console the respective page directly and query it's data-url, it shows the correct value. So how come the above still gives me undefined on iOS
undefined
while working correctly everywhere else?
Thanks for any hints!
EDIT:
The element will be dynamic, but I can console for the page in my setup directly like so:
console.log( $('div:jqmData(wrapper="true").ui-page-active').attr('id') );
console.log( $('div:jqmData(wrapper="true").ui-page-active').attr('data-url') );
Both return the correct id and data-url, so the elements must exist.
EDIT2:
I can query for the attribute data-url which gives me the correct value. However, I cannot select using this attribute like so:
$('div[data-url="'+$currentEntry+'"]').length
which gives me 0
I am going to admit that I am blind-guessing, but you should try:
$activePage = $('div').filter(function(){return $(this).jqmData('url') === $currentEntry})
BTW, just for semantics i think "$currentEntry" shouldn't start with a dollar sign if it is not a jQuery object.

Chrome extension read innerHTML of the current page?

Hi this may be a silly question, but I can't find the answer anywhere.
I'm writing a chrome extension, all I need is to read in the html of the current page so I can extract some data from it.
here's what I have so far:
<script>
window.addEventListener("load", windowLoaded, false);
function windowLoaded() {
alert(document.innerHTML)
});
}
</script>
Can anybody tell me what I'm doing wrong?
thanks,
function windowLoaded() {
alert('<html>' + document.documentElement.innerHTML + '</html>');
}
addEventListener("load", windowLoaded, false);
Notice how windowLoaded is created before it is used, not after, which won't work.
Also notice how I am getting the innerHTML of document.documentElement, which is the html tag, then adding the html source tags around it.
I'm writing a chrome extension, all I need is to read in the html of
the current page so I can extract some data from it.
I think an important answer here is not the correct code to use to alert the innerHTML but how to get the data you need from what's already been rendered.
As pimvdb pointed out, your code isn't working because of a typo and needing document.documentElement.innerHTML, something you can diagnose in the Chrome console (Ctrl+Shift+I). But that's secondary to why you'd want the inner HTML in the first place. Whether you're looking for a certain node, specific text, how many <div> elements exist, the value of an ID, etc., I'd heavily recommend the use of a library like jQuery (vanilla JS works, but it can be verbose and unwieldy). Instead of reading in all the HTML and parsing it with string functions or regex, you probably want to take advantage of all the DOM parsing functionality already available to you.
In other words, something like this:
$("#some_id").val(); // jQuery
document.getElementById("some_id").value; // vanilla JS
is probably way safer, easier and more readable than something eminently breakable like this (probably a bit off here, but just to make a point):
innerHTML.match(/<[^>]+id="some_id"[^>]+value="(.*?)"[^>]*?>/i)[1];
Use document.documentElement.outerHTML. (Note that this is not supported in Firefox; irrelevant in your case.) However, this is still not perfect as it doesn't return nodes outside the root element (!doctype and possibly some comments or processing instructions). The document.innerHTML property is, AFAIK, specified in HTML5 specification, but currently not supported in any browser.
Just FYI, navigating to view-source:www.example.com also displays the entire markup (Chrome & Firefox). But I don't know whether you can work with it somehow.
window.addEventListener("load", windowLoaded, false);
function windowLoaded() {
alert(document.documentElement.innerHTML);
}
You had a } with no purpose, and the }); should just be }. These are syntax errors.
Also, it's document.documentElement.innerHTML, since it's not a property of document.

Whats happening? One day its OK, the next day its 'undefined'?

I am writing a greasemonkey script. Recently i had this same problem twice and i have no idea why is this happening.
function colli(){
.....
var oPriorityMass = bynID('massadderPriority');//my own document.getElementById() function
var aPriorities = [];
if (oPriorityMass) {
for (var cEntry=0; cEntry < oPriorityMass.childNodes.length; cEntry++) {
var sCollNumber = oPriorityMass.childNodes[cEntry].getAttribute('coll');
if (bynID('adder' + sCollNumber + '_check').checked)
aPriorities.push(parseInt(sCollNumber));
}
}
.....
}
So the mystery of this is, one day i had oPriorityMass named as oPririoty. It was working fine, but the whole function was not yet complete and i started working on another functions for my script. These functions have no connection with each other.
Few days later i decided to go back to my function in the above example and finish it. I ran a test on it without modifying anything and got an error in the firefox's (4) javascript error console saying that oPriority.chilNodes[cEntry] is undefined. NOTE, few days back i have tested it exactly the same way and there was no such problem at all.
Ok, so, i decided to rename oPriority to oPriorityMass. Magically, problem got solved.
At first i thought, maybe there was some conflict of 2 objects, with the same name being used in different functions, which somehow continued to live even outside of function scope. My script is currently over 6000 lines big, but i did a search and found out that oPriority was not mentioned anywhere else but in this exact function.
Can somebody tell me, how and why is this happening? I mentioned same thing happened twice now and they happened in different functions, but the same problem node.childNodes[c] is undefined yet node is not null and node.childNodes.length show correct child count.
What is going on? How do i avoid such problems?
Thank you
EDIT: The error given by error console is
Error: uncaught exception: TypeError: oPriorityMass.childNodes[cEntry] is undefined
In response to Brocks comment:
GM_log(oPriorityMass.childNodes[cEntry]) returns undefined as a message. So node.childNodes[c] is the thing that is undefined in general.
My script creates a div window. Later, the above function uses elements in this div. Elements do have unique IDs and i am 100% sure the original site don't know about them.
My script has a start/stop button to run one or the other function when i need to.
I have been refreshing the page and running my script function now. I have noticed that sometimes (but not always) script will fail with the described error on the first run, however, if i run it again (without refreshing the page) it starts working.
The page has a javascript that modifies it. It changes some of it's element widths so it changes when the browser is resized. But i know it has no effect on my div as it is left unchanged when i resize browser.
EDIT2:
function bynID(sID) {
return top.document.getElementById(ns(sID));
}
function ns(sText) {
return g_sScriptName + '_' + sText;
}
ns function just adds the script name in front of the ID. I use it when creating HTML element so my elements never have the same id as the web page. So bynID() is simple function that saves some typing time when i need to get element by ID.
I have modified my colli() function to include check
if (oPriorityMass) {
if (!oPriorityMass.childNodes[0]) {
GM_log('Retrying');
setTimeout(loadPage,2000);
return;
}
for (var cEntry=0; cEntry < oPriorityMass.childNodes.length; cEntry++) {
var sCollNumber = oPriorityMass.childNodes[cEntry].getAttribute('coll');
if (bynID('adder' + sCollNumber + '_check').checked)
aPriorities.push(parseInt(sCollNumber));
}
}
The loadPage function does 1 AJAX call, then i run few XPATH queries on it, but the actual contents are never appended/shown on the page, just kept inside document.createElement('div'), then this function calls colli(). So now, as i have modified my function, i checked the error console and saw that it may take up to 5 tries for it to start working correctly. 5 x 2seconds, thats 10 seconds. It is never 5 retries always, may vary There's got to be something else going on?
In Firefox, childNodes can include #text nodes. You should check to make sure that childNodes[cEntry] has nodeType == 1 or has a getAttribute method before trying to call it. e.g.
<div id="d0">
</div>
<div id="d1"></div>
In the above in Firefox and similar browsers (i.e. based on Gecko and WebKit based browsers like Safari), d0 has one child node, a text node, and d1 has no child nodes.
So I would do something like:
var sCollNumber, el0, el1;
if (oPriorityMass) {
for (var cEntry=0; cEntry < oPriorityMass.childNodes.length; cEntry++) {
el0 = oPriorityMass.childNodes[cEntry];
// Make sure have an HTMLElement that will
// have a getAttribute method
if (el0.nodeType == 1) {
sCollNumber = el0.getAttribute('coll');
el1 = bynID('adder' + sCollNumber + '_check');
// Make sure el1 is not falsey before attempting to
// access properties
if (el1 && el1.checked)
// Never call parseInt on strings without a radix
// Or use some other method to convert to Number
aPriorities.push(parseInt(sCollNumber, 10));
}
}
Given that sCollNumber seems like it is a string integer (just guessing but it seems likely), you can also use:
Number(sCollNumber)
or
+sCollNumber
whichever suits and is more maintainable.
So, according to your last edit, it now works, with the delay, right?
But when I suggested the delay it was not meant to do (even more?) ajax calls while waiting!!
NOT:
if (!oPriorityMass.childNodes[0]) {
GM_log('Retrying');
setTimeout(loadPage,2000);
return;
More like:
setTimeout (colli, 2000);
So the ajax and the other stuff that loadPage does could explain the excessive delay.
The random behavior could be caused by:
return top.document.getElementById(ns(sID));
This will cause erratic behavior if any frames or iframes are present, and you do not block operation on frames. (If you do block such operation then top is redundant and unnecessary.)
GM does not operate correctly in such cases -- depending on what the script does -- often seeming to "switch" from top scope to frame scope or vice versa.
So, it's probably best to change that to:
return document.getElementById (ns (sID) );
And make sure you have:
if (window.top != window.self) //-- Don't run on frames or iframes
return;
as the top lines of code.
Beyond that, it's near impossible to see the problem, because of insufficient information.
Either boil the problem into a Complete, Self Contained, Recipe for duplicating the failure.
OR, post or link to the Complete, Unedited, Script.

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