setting onclick in javascript is not working - javascript

So I'm writing some function that is working with Facebook's API. I was previously setting the onclick attribute by taking the parent and saying something along the lines of parent.innerHTML += "<a onclick = 'test("+parameter+")'>Previous</a>" and that worked fine. But I wanted to make it safer and more to standard so it is styled as follows:
function myMethod(link){
...
FB.api(link, function(response){
...
if(value != null){
var prev = document.createElement("a");
prev.innerText = "previous";
prev.setAttribute("id", "previous");
//prev.onclick = function(){test(this);}; doesn't work here
document.getElementById("facebook-photos").appendChild(prev);
}
//some other code (loops and stuff) including this
for(...){
var container = document.createElement("div");
container.classList.add("container");
container.classList.add("thing");
container.onclick = function(){test(this);}; // works here
}
//
if(document.getElementById("previous")){
document.getElementById("previous").onclick = function(){test(this);}; //works here
}
}
}
yet for some reason whenever I try and use this, clicking the element does nothing. Inspecting the element shows no "onclick" field but displaying the element in the console shows that the onclick field is not null. Nothing is covering the element and I've tried it as a div and as a button. When I try and do document.getElementById("previous") earlier, it still doesn't work. Why does this happen? Is it just the asynchronous nature of Javascript? The assignment in the middle works even though its relatively soon after the creation of the element, but the one at the beginning does not.

Related

my sapUI5 app only jumps once into my print method

this is my very first question on Stackoverflow. I am currently developing a print function in my sap ui5 app to print out certain UI controls. I've got the function from here: http://embed.plnkr.co/jjyEPa1updkjBiNZqumS/preview
However, during runtime, when I click on the print button, my app only jumps to the method once and executes it correctly (to print). But after that, I can press the printbutton as often as I want, nothing happens and I can't find out why.
what the method does: i replace the body with a temporary body, which only contains the elements to be printed and execute window.print(). afterwards i insert the original body content again. Of course I use the UI controls to grab the HTML tags.
onPrintChart: function(oEvent){
var oTarget = this.getView(),
sTargetId = oEvent.getSource().data("targetId");
if (sTargetId) {
oTarget = oTarget.byId(sTargetId);
}
if (oTarget) {
var $domTarget = oTarget.$()[0],
sTargetContent = $domTarget.innerHTML,
sOriginalContent = $(document.body)[0].innerHTML;
$(document.body)[0].innerHTML = sTargetContent;
window.print();
$(document.body)[0].innerHTML = sOriginalContent;
} else {
jQuery.sap.log.error("onPrint needs a valid target container [view|data:targetId=\"SID\"]");
}
}
I managed to do it in a different, more elegant way without using a temporary body. I used CSS to hide all irrelevant elements (display: none) and keep only the relevant element for printing.
Apparently ui5 hung up when replacing the original body temporarily with another body. I noticed that ALL buttons didn't work anymore, not only the print button.

Button onClick Event Listener not working in Electron app

Background:
I am using ElectronJS to make a game and I have a class for a shop which I named Shop.
It has a method that I call 'createItemElement' which takes an object named 'item' and creates an li element to be later added to a ul element. The code for this can be found below.
class Shop {
// ...
createItemElement(item) {
// Item Container
const li = document.createElement("li");
// Title
const title = document.createElement("h3");
title.textContent = item.title;
// Info
const info = document.createElement("p");
info.textContent = `Type: ${item.type}`;
// Add to Cart
const addButton = document.createElement("button");
addButton.textContent = "Add to Cart";
addButton.onclick = () => console.log("Adding to cart!");
li.appendChild(title);
li.appendChild(info);
li.appendChild(addButton);
return li;
}
// ...
}
Problem:
Interestingly, all of the HTML is correctly rendered and everything looks as it should, but the 'onclick' event just plain does not work.
Since all of these elements are in fact being rendered, it should be safe to assume that the code is indeed being run in the renderer process.
For some reason, however, the event is not being carried over to the app.
When I click the button in the app, nothing happens.
I checked the devTools and looked at the elements individually.
As expected, all of the elements were listed out correctly in element inspector, but when I inspected that 'addButton' button, there was no 'onclick' property to be seen.
Also, there are no errors in the console whatsoever, so that's nice (sarcasm).
And I am aware that there are many seemingly similar questions asked on StackOverflow, but none of the answers that I found have helped or applied to my situation.
It is extremely confusing as to why the elements are being rendered perfectly but the event listener is not working.
The full project can be found here and the file being excerpted below can be found here.
I looked at your shop.js page, and you incorrectly camel-case the onclick event in one place, but not in another. Using the camel-cased version of onclick will yield no error and do nothing.
Won't work:
empty_cart_button.onClick = (evt) => this.emptyCart();
Works:
addButton.onclick = () => this.addToCart(item);
As I can see from you're code, you're using el.innerHTML in the shop instance .getHTML() method. this will return the inner HTML as a raw string without any event listeners, this is why you see the rendered content as expected but the click listener doesn't work.
In the sketch.js file, the toggleShop function should use appendChild so instead of:
document.querySelector("#shop-container").innerHTML = shop.getHTML();
you should do:
document.querySelector("#shop-container").appendChild(shop.getElement())
and in the Shop class add the getElement method:
getElement() {
return this.el;
}
Be sure to toggle the shop and remove the #shop-container innerHTML when you want to toggle it off.
Also, as #Andy Hoffman answered, you should set the onclick property and not the onClick.

Firing a manual click event on an button in ember.js doesn't give the required result

TL;DR: Trying to fire a manual javascript click event on the chat button of twitch, won't send the message. Don't understand why the event doesn't do the same as a normal click and don't know how to make it work.
So I am trying to make a custom bot for twitch.tv, only reading his info from the HTML directly. I've got it perfectly working up to the point at where it can recognize commands and put text in the textbox. Now the problem I have is, as soon as I try to fire a manual click event on the "chat" button, it just doesn't seem to work. My guess is it has something to do with ember.js, and I frankly don't know anything about that. Anyway, here is the part of the code that doesn't work. EDIT: this works if I enter it as single in the console, doesn't work in context of the rest of my code though.
$('.send-chat-button').click();
What happens here is that I acquire a piece of html that contains the chat submit button, which is this:
<button class="button primary float-right send-chat-button" data-bindattr-3945="3945">
<span>
Chat
</span>
</button>
When I try to manually fire a click event on this, nothing happens. However, when I fire a manual click event on buttonContain.children[0] and buttonContain.children1 (which are, respectively, the settings and list of viewers buttons), it does work. They look like this:
<a data-ember-action="3943" class="button glyph-only float-left" title="Chat Settings"></a>
I'm guessing the difference is in the data-ember-action and the data-bindattr-*, but I don't know how to make it work. Anyone here knows why the click() event doesn't work and directly clicking does?
EDIT: If you have any questions about my question, feel free to ask.
EDIT2: I experimented a little more, and I can remove all HTML attributes from the button, and clicking on it will still work. I have no idea what is going on :(.
EDIT3: Okay, so it seems it only stops working when i remove the
Span within the button
Still no idea what is going on. (Yes, have also tried to fire the click event on the span)
EDIT4: As requested, here is all the code from my side. Note that I'm trying to click a button from twitch itself, of which ember side I do not own any code. This code is used by pasting it in the console on a twitch.tv stream and then starting it by calling initiateMessageProcessing. I'm sorry for the lot of hardcoded values, those are twitch' fields that I need. For now I'm just looking for a proof of concept.
var frequency = 5000;
var myInterval = 0;
var lastMessageId = 0;
function initiateMessageProcessing() {
if (myInterval > 0) {
clearInterval(myInterval);
}
myInterval = setInterval("checkMessages()", frequency);
}
function checkMessages() {
var chat = document.getElementsByClassName("chat-lines")[0];
processMessages(extractUnprocessedMessages(chat.children));
lastMessageId = parseInt(chat.lastElementChild.getAttribute("id").substring(5, 10));
}
function extractUnprocessedMessages(chat) {
var unprocessedMessages = [];
var chatId = 0;
for ( i = 0; i < chat.length; i++) {
chatId = parseInt(chat[i].getAttribute("id").substring(5, 10));
if (chatId > lastMessageId) {
unprocessedMessages.push(chat[i]);
}
}
return unprocessedMessages;
}
function processMessages(unprocessedMessages) {
var messageElement;
for ( i = 0; i < unprocessedMessages.length; i++) {
messageElement = unprocessedMessages[i].children[0].getElementsByClassName("message")[0];
if (messageElement != undefined && messageElement != null) {
if (messageElement.innerHTML.search("!test") !== -1) {
sendMessage('Hello world!');
}
}
}
}
function sendMessage(message) {
fillTextArea(message);
var button = $('.send-chat-button').get(0);
var event = new MouseEvent('click', {
bubbles : true
});
button.dispatchEvent(event);
}
function fillTextArea(message){
var textArea;
var chatInterface = document.getElementsByClassName("chat-interface")[0];
var textAreaContain = chatInterface.children[0];
textArea = textAreaContain.children[0].children[0];
textArea.value = message;
}
EDIT5: Eventlistener screenshot:
EDIT6: Edited source code to use $('.send-chat-button').click();
I have tried this, does not work in the current code, it does work if I manually fire this single command in the console when there is text in the chat. But sadly does not work in my code.
EDIT7: used Ember.run, still doesn't work.
EDIT8: used dispatchmouseevent, still doesn't work in context of code
It seems that the target site attaches event listeners without help of JQuery. If it is so, you cannot trigger it using jquery .click() method.
You can try directly mocking the browser event like this:
var button = $('.send-chat-button').get(0);
var event = new MouseEvent('click', {bubbles: true});
button.dispatchEvent(event);
This code will not work in IE8 and lower, but I guess it is not your case.
I know this post is quite old but I had been looking for an answer on this for a while and nothing really worked, after trying out A LOT of stuff I found it works when you focus the chatbox first then focus the button then triggering the click event!!! uuuhm yeah...
$('.chat_text_input').focus();
$('.send-chat-button').focus().trigger('click');
I have no idea why this works (and why it doesn't in any other way), but leaving any of the focusses out makes it fail or bug out.
Programmatically clicking a DOM element to make some action done is somewhat a wrong approach.
You should have define a method myAction() which will be called in two ways. First, from your ember action triggerMyAction() and second, after listening to a custom event, "myEvent".
Instead of $('.send-chat-button').click(); you will code $('something').trigger("myEvent") then.
Something like:
Em.Controller.extend({
myAction:function(){
//do your stuff
},
onMyEvent:function(){
$('something').on('myEvent',this.myAction);
}.on('didInsertElement'),
actions:{
triggerMyAction:function(){
this.myAction();
}
}
})

userscript: I lost some JS?

I do not understand what's going on...
I have a simple userscript, that add couple DIVs, css styles and JS functions in the pages I visit
In particular, I have one DIV that trigger a JS function with a onClick listener - this function is a "toggle" function (display/hide an other DIV):
function togglegm(etat) {
if (etat = 'on') {
document.getElementById('greasemky').style.display = 'block';
document.getElementById('greasemkytoggle').innerHTML = '';
} else if (etat = 'off') {
document.getElementById('greasemky').style.display = 'none';
document.getElementById('greasemkytoggle').innerHTML = '';
}
}
var script2 = d.createElement('script');
script2.appendChild(d.createTextNode(togglegm));
(d.body || d.head || d.documentElement).appendChild(script2);
The DIV "greasemkytoggle" only contains a link with a onClick that trigger "togglegm('on'), and my objective is that when togglegm(on) is executed, the innerHTML of this DIV becomes a trigger for togglegm(off).
Now the weird part... when I click on my DIV greasemkytoggle, the function togglegm(on) is perfectly executed (greasemky is displayed), and the innerHTML is perfectly changed with a link for "togglegm(off)", BUT if I click again, then nothing happens.
I looked at the source code, and discovered that my JS function just disappeared (that's why nothing happened on the last click)! Now, there is an empty function replacing my togglegm():
<script>
scriptHolderArray1
</script>
Do you understand that kind of behaviour...?
I found nothing online for that kind of situation...
GreaseMonkey runs under a much more security conscience set of rules.
Attach the event listeners using the proper DOM3 (addEventListener) method.
It is never a good idea (in user scripts or general scripting) to assign Javascript through innerHTML.
It is never a good idea to use the "javascript:" pseudo-protocol.
The problems are etat = 'on' and etat = 'off'.
If you want to set values, use
etat = 'on'
etat = 'off'
If you want to compare, use:
etat == 'on'
etat == 'off'
Moreover, href="javascript:return(false);" throws an error on Firefox because there is a return outside a function (SyntaxError: return not in function). You should do href="javascript:void(0);", or return false at the end of the onclick event.
Anyway, I don't understand very well what you are doing here:
var script2 = d.createElement('script');
script2.appendChild(d.createTextNode(togglegm));
(d.body || d.head || d.documentElement).appendChild(script2);
You have a function togglegm loaded to browser's memory by a <script> element.
Then, you create a new <script> with that function and append it to the document, in order to load it to browser's memory again (I guess).
Why?

Javascript working on Firefox but not in Chrome and IE6

I have javascript that working fine in Firefox 3.x.x, but it does not work in IE*, Chrome, Safari. Simple alert work before calling function. Here is the code
function showDiv(div){
//alert(div);
document.getElementById(div).style.visibility='visible';
document.getElementById(div).style.height='auto';
document.getElementById(div).style.display='block';}
function hideDiv(div){
//alert(div);
document.getElementById(div).style.visibility='hidden';
document.getElementById(div).style.height='0px';
document.getElementById(div).style.display='none';
}
here is the html page code
<td align="center"><a onclick="showDiv('<?=$val['keyname']?>')" style="cursor:pointer;">Edit</a></td>
if I put alert() before showDiv('<?=$val['keyname']?>') then alert box is displayed but the function is not called in other browsers other than fire fox
Please tell me the solution for this.
The syntax looks okay to me.
Make sure there are not multiple elements with the same ID in the document and that your element IDs are valid.
There is nothing inherently wrong in the code you have posted. I suggest you post a reproduceable non-working example: the problem will be elsewhere in the page. Maybe the div ID string isn't unique (this is invalid HTML and will make behaviour unreliable); maybe there's some other script interfering, maybe you have event code firing this that's not written in a cross-browser way
However your attempts to hide an element in three different ways seem like overkill to me. Just a single display change would do it fine.
Another way to do it is to set className='hidden' or '', and use a CSS rule to map that class to display: none. The advantage of this is that you don't have to know whether the element in question is a <div> (that should revert to display: block), a <span> (that should revert to display: inline) or something else. (The table-related elements have particular problems.)
Maybe you could try that:
function showDiv(div) {
var obj = document.getElementById(div);
if (obj) {
obj.style.display = "block";
obj.style.height = "auto";
} else {
alert("DIV with id " + div + " not found. Can't show it.");
}
}
function hideDiv(div) {
var obj = document.getElementById(div);
if (obj) {
obj.style.display = "none";
} else {
alert("DIV with id " + div + " not found. Can't hide it.");
}
}
Do not call document.getElementById several times in the same function, use a variable to store the div element.
The if (obj) test will only execute the code if it has been found by document.getElementById(...).

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