I'm working on something where multiple functions will add various Event listeners to an initially hidden div, let's just call it secretBlock. Only one will ever be active at any given point, but all said functions will manipulate it by:
First cloning sercetBlock to ensure no previous listeners are still attached
Then setting the display to flex
HTML:
<div id="secretBlock" hidden>Secret</div>
JavaScript:
function exampleFuction() {
var secretBlock = document.getElementById('secretBlock');
var secretClone = secretBlock.cloneNode(true);
secretBlock.parentNode.replaceChild(secretClone, secretBlock);
secretBlock.style.display = 'flex';
....
}
but the last part, setting the display, is not firing.
I assumed this had something to do with async-ness, but
setTimeout(function(){ secretBlock.style.display = 'flex' }, 999);
also had no effect.
However, one of the functions appends the div inside of another div right after setting the display, causing it to fire properly:
secretBlock.parentNode.replaceChild(secretClone, secretBlock);
secretBlock.style.display = 'flex';
otherDiv.appendChild(secretBlock);
After a bit of testing, I found out it doesn't matter when I set the display (now vs later) or where it is in the code, as long as secretBlock gets appended to another div, the display change will register, otherwise staying hidden.
.......which sorta left me clueless as to what's going on, any insight would thus be much appreciated~~
Was a reference issue.
After .replaceChild() replaces secretBlock, the initial reference:
var secretBlock = document.getElementById('secretBlock')
becomes obsolete as it still points to the old, original element which is not apart of the html document anymore. Thus you need to redirect the reference to the cloned element:
secretBlock.parentNode.replaceChild(secretClone, secretBlock);
secretBlock = document.getElementById('secretBlock');
secretBlock.style.display = 'flex';
Thanks Dr.Molle!
Related
I am trying to write a ToDoList with JavaScript.
I have an input-element. Whenever I type something and press enter, it creates a new fieldset(in my example its a fieldset but it can also be a Div) with the class name ".fieldListClass" and a P-Tag as a child of fieldset. the P-tag innerHTML is the the value of input. I used Click-EventListener for that.
After each click, I assigned the query selector of all .fieldListClass to a nodeList "fieldListQuery". I even converted this nodeList into an Array but no result.
Now I want to create an addEventListner but outside the previous one. it should be a new one. And It should be a click-EventListener for all fieldListQuery which where created inside the previous function.(this part is at the bottom of my code)
When I click on it something should happen like removing the current target etc. But it wont work because outside the function it always says that this variable is undefined. I don't get it because I declared it global outside of the function.
I don't want to use DOMNodeInserted or MutationObserver yet for detecting changes inside the DOM. Simple because the first one is not recommended anymore it and the last one I have no idea how to use it. Many people saying that this is not a safe way.
Any Help please?
let addDiv = document.createElement("div"); addDiv.id = "addDivId";
let listDiv = document.createElement("div"); listDiv.id = "listDivId";
let inputText = document.createElement("input"); inputText.id = "inputTextId";
let fieldList; // = document.createElement("fieldset");
let fieldDiv; // = document.createElement("div");
let fieldDivP; // = document.createElement("P");
let fieldListArr;
let fieldListQuery;
document.body.appendChild(addDiv);
addDiv.appendChild(inputText);
document.body.appendChild(listDiv);
inputText.addEventListener("keypress", event => {
if (event.key === "Enter") {
fieldList = document.createElement("fieldset");
fieldDiv = document.createElement("div");
fieldDivP = document.createElement("P");
listDiv.appendChild(fieldList);
fieldList.className = "fieldListClass";
fieldList.appendChild(fieldDiv);
fieldDiv.appendChild(fieldDivP);
fieldDivP.innerHTML = inputText.value;
fieldListQuery = document.querySelectorAll(".fieldListClass") ;
}
})
fieldListQuery.forEach(element => { // <- it say fieldListQuery is undefined.
fieldListQuery.addEventListener("click", e => {
e.currentTarget.innerHTML="test";
})
});
´´´
Since I offered critique of your approach, I thought it is only fair I at least try to offer you some code that accomplishes (on the overall level, in light of absence of much detail about your solution) something along of what you have.
First off, I think creating trees of elements through a script when other solutions are more viable, tends to show an anti-pattern. Your script is invariably loaded in the context of an HTML document, which may already contain a lot of useful markup -- including an input field (that you were creating with createElement). If the input field is a "constant" there is no need to waste code on creating it -- just put it in your markup.
Second, even for elements or hierarchies of elements that are created "on demand" -- as a reaction to an event or however else -- it typically is much more readable and manageable to use templates. As a fallback -- if template cannot be used for some reason -- using innerHTML to create entire element trees is actually an appealing and more readable option than a lot of "boilerplate" containing createElement, appendChild, etc.
Third, you should always try to see if you can have your interactive controls be part of a form. I won't go into all reasons to do so, but suffice to say it helps user agents that screen-read content and for other accessibility systems, to name one. There are exceptions to this rule, but I don't recall looking at code where a control should not be part of a form -- so the rule is a good one.
Here is a proof-of-concept bare-bones to-do application:
<html>
<head>
<script>
function submit_create_todo_item_form() {
const new_todo_fragment = document.getElementById("todo-item-template").content.cloneNode(true);
new_todo_fragment.querySelector(".body").textContent = document.forms[0].elements[0].value;
document.body.appendChild(new_todo_fragment);
}
</script>
<template id="todo-item-template">
<div class="todo-item">
<p class="body"></p>
</div>
</template>
</head>
<body>
<form action="javascript: submit_create_todo_item_form()">
<input>
</form>
</body>
<html>
Take note that I use textContent instead of innerHTML to create content for a to-do item's body. innerHTML invokes the HTML parser and unless you plan to be typing hypertext into that single line of input field, innerHTML only costs you extra for no clear benefit. If you need to interpret the value verbatim, textContent is instead exactly what's needed. So, approach your solution with that in mind.
I hope this is useful, I worked with what I thought I had.
Dynamically swapping BODY content using jQuery html function works as expected with 'static' content.
But if forms are being used, current state of inputs is lost.
The jQuery detach function, which should keep page state, seems to be blanking out the whole page.
The following code is the initial idea using jQuery html but of course the text input value will always empty.
function swap1( ) {
$("body").html('<button onclick="swap2();">SWAP2</button><input type="text" placeholder="swap2"/>');
}
function swap2( ) {
$("body").html('<button onclick="swap1();">SWAP1</button><input type="text" placeholder="swap1"/>');
}
With not knowing what form inputs there are, how would one swap in and out these forms in the BODY and keep track of the form states?
Demo of two text inputs which should keep state when they come back into the BODY:
https://jsfiddle.net/g7hksfne/3/
Edit: missunderstood use case. This covers saving the state while manipulating the DOM, instead of switching between different states.
Instead of replacing the <body>'s content by serializing and parsing HTML, learn how to use the DOM. Only replace the parts of the DOM you actually change, so the rest of it can keep its state (which is stored in the DOM).
In your case: you might want to use something like this:
function swap1( ) {
document.querySelector("button").onclick = swap2;
document.querySelector("button").textContent = "SWAP2";
document.querySelector("input").placeholder = "swap2";
}
function swap2( ) {
document.querySelector("button").onclick = swap1;
document.querySelector("button").textContent = "SWAP1";
document.querySelector("input").placeholder = "swap1";
}
<button onclick="swap1();">SWAP1</button><input type="text" placeholder="swap1"/>
(This is not optimized and should only serve as an example.)
Put the content you want to save in a node below <body>, like a simple ´` if you don't already have a container. When you want to save and replace the container, use something like:
var saved_container = document.body.removeChild(document.querySelector("#app_container");
// or document.getElementById/getElementsByClassName, depends on container
The element is now detached and you can add your secondary to document.body. When you want to get back, save the secondary content (without overwriting the first container of course), then reattach the primary content it with:
document.body.appendChild(savedContainer);
I have following code working so far: JSFIDDLE DEMO
The relevant JS is here:
// Define classes & background element.
var classes = ['bg1','bg2','bg3','bg4'],
$bg = document.getElementById('blah');
// On first run:
$bg.className = sessionStorage.getItem('currentClass') || classes[0];
// On button click:
$('.swapper').mousedown(function () {
// (1) Get current class of background element,
// find its index in "classes" Array.
var currentClassIndex = classes.indexOf($bg.className);
// (2) Get new class from list.
var nextClass = classes[(currentClassIndex + 1)%classes.length];
// (3) Assign new class to background element.
$bg.className = nextClass;
// (4) Save new class in sessionStorage.
sessionStorage.setItem('currentClass', nextClass);
});
For my purposes, this functionally working great -- I can click a single button to continually swap between those four classes while also storing the current class to sessionStorage, so that when I click links on my website, the currentClass is loaded right away. (Note: on my website the setup is the same, but the classes bg1, bg2, bg3, and bg4 contain background images.)
What I'd like it to do:
When swapping from one class to another, I'd like it to do a quick/short cross-fade. Right now it just snaps from one class/background to another.
My thinking was: is there a way I can trigger a CSS class transition or animation that contains the fade, perhaps as a parent class? I know there's a jQuery fade function, but I haven't been able to get it working with my setup so that it triggers on mouseClick.
Here's an updated jsfiddle based on your comment where you said you've sort of having it work.
I've added the timeout functions
setTimeout(function(){$bg.className = nextClass}, 500);
setTimeout(function(){$($bg).fadeIn(500)}, 500)
The first timeout makes it so that the image is swapped right after the first image fades out. The second timeout gives it a bit of time to load in so it's not so jittery.
You can play with the }, 500); number to get it timed just like you want, 500 is half a second, 1000 is a second etc.
I'm making a simple lightbox. If you click on an image, it takes that image and shows it full screen with a black background behind it.
Here is my code:
$('.theContent img').live('click', function(e) {
var lbImg = $(this);
$('#lb').toggle();
$('#lb').find("#lbImg").append(lbImg);
)
Thing is, it takes away the variable lbImg and puts it in the lightbox. I dont want that, i just want to copy that bit of info and duplicate, rather than reposition. How would you go about that?
Use the .clone() method to copy the element:
var lbImg = $(this).clone();
Normally, when an element is re-appended, it is removed from the previous location. When an element have to be appended without removing it from the previous spot, it has to be duplicated.
I have an element in my document that has a background color and image set through a regular CSS rule.
When a certain event happens, I want to animate that item, highlighting it (I'm using Scriptaculous, but this question applies to any framework that'll do the same).
new Effect.Highlight(elHighlight, { startcolor: '#ffff99', endcolor: '#ffffff', afterFinish: fnEndOfFadeOut });
The problem i'm facing is that after the animation is done, the element is left with the following style (according to FireBug):
element.style {
background-color:transparent;
background-image:none;
}
Which overrides the CSS rule, since it's set at the element level, so I'm losing the background that the item used to have...
What I'm trying to do is, in the callback function I'm running after the animation is done, set the style properties to a value that'll make them "go away".
var fnEndOfFadeOut = function() {
elHighlight.style.backgroundColor = "xxxxx";
elHighlight.style.backgroundImage = "xxxxx";
}
What I'm trying to figure out is what to put in "xxxx" (or how to do the same thing in a different way).
I tried 'auto', 'inherit', and '' (blank string), and neither worked (I didn't really expect them to work, but I'm clueless here).
I also tried elHighlight.style = ""; which, expectably, threw an exception.
What can I do to overcome this?
I know I can put a span inside the element that I'm highlighting and highlight that span instead, but I'm hoping I'll be able to avoid the extra useless markup.
Chances are you're not setting the style on the correct element. It's probably being set somewhere up the line in a parent node.
elHighlight.style.backgroundColor = "";
elHighlight.style.backgroundImage = "";
You can also remove all the default styling by calling:
elHighlight.style.cssText = "";
In any case, you'll still have to do this on the specific element that is setting these properties, which means you may need to do a recursion on parentNode until you find it.
Try
elHighlight.style.removeProperty('background-color')
elHighlight.style.removeProperty('background-image')
have you tried elHightlight.style.background = "";?
I have a highlighter code on my site and this works
function highlight(id) {
var elements = getElementsByClass("softwareItem");
for (var ix in elements){
elements[ix].style.background = ""; //This clears any previous highlight
}
document.getElementById(id).style.background = "#E7F3FA";
}
An HTML element can have multiple CSS classes. Put your highlight information inside a CSS class. Add this class to your element to highlight it. Remove the class to undo the effect.