I want to select an element if it has a css as display block then do this function. If the element has the css as display block then remove ('hide') class from the header class.. This is what I want to do.. Any help?
Well, there are two solutions depending on what you want:
Solution 1
Looping through all elements and removing hide class from the current element if it has display block value in its style.
var elements = document.getElementsByTagName("*");
for(let i = 0; i < elements.length; i++) {
if(elements[i].style.display == "block") {
elements[i].classList.remove("hide");
}
}
Solution 2
Getting the reference of the element via HTML id.
var element = document.getElementById("YourElementID");
if(element.style.display == "block") {
element.classList.remove("hide");
}
You can define an id like this in your HTML file:
<div id="YourElementID">Div</div>
I am assuming that you want to determine if the element has the "hide" class by checking its display style. you don't need to do that, you can easily check its class list by using the following code:
element.classList.contains("hide");
There are several ways of collecting all the elements with display: block and i am not sure, which one performs best - or whether it performs good at all.
If you want all the Element instances of the page, which have a computed style of display: block you can do something like:
var $els = Array.from(document.body.querySelectorAll('*')).filter(function($el) {
return getComputedStyle($el).display === 'block';
});
Or ES6:
const $els = Array.from(document.body.querySelectorAll('*')).filter($el => getComputedStyle($el).display === 'block');
If you want the Element instances which have display: block literally set in the style-attribute, you have to do something like this:
var $els = Array.from(document.body.querySelectorAll('*')).filter(function($el) {
return $el.style.display === 'block';
});
I think it would perform better, if the selector in querySelectorAll() would be a little more specific.
Another option would be to use the TreeWalker API, but then you have to do a mutation, because you have to iterate over all the elements and push them to an array:
var $els = [];
walker = document.createTreeWalker(document.body, NodeFilter.SHOW_ELEMENT);
while (walker.nextNode()) {
if (getComputedStyle(walker.currentNode).display === 'block') {
$els.push(walker.currentNode);
}
}
Once you have all your elements, you can do something with them.
A little bit more information would be helpful, especially what exactly you want to achieve, once you have the elements, because then i could also provide more help. Maybe provide a code example?
Related
I need to use JS to create a new element within specific nested classes in HTML. So in this example, I need to create a new span with the class of "paw-print" only where the "collies" class is nested within "dogs".
Here's what I have so far: https://jsfiddle.net/p50e228w/6/
The problem is that my current JS works on the first instance, but not on the other. I currently have document.getElementsByClassName set to "collies" but I need to target that class only when it's inside the parent "dogs" class.
What am I missing here?
var span = document.createElement("span");
span.className = "paw-print";
var wrap = document.getElementsByClassName("collies");
for(var i = 0; i < wrap.length; i++) {
wrap[i].appendChild(span);
}
I can use jQuery, but I've been using vanilla JS just because I'm such a noob and want to understand what my code is doing.
There are 2 issues with your code.
Positioning : The images are being given a absolute position, and they rest in the same position based on the page layout. So set relative positioning for the parent container.
CSS
.relative {
position: relative;
}
You need to append that to parent element which is collie here.
You can use querySelectorAll to find the nested relation ship that you are looking for.
var collies = document.querySelectorAll('.dogs .collies');
for (var i = 0; i < collies.length; i++) {
var span = document.createElement("span");
span.className = "paw-print";
collies[i].appendChild(span);
}
Fiddle
If you want to append to parent ( element with class 'dog')
$('.dogs .collies').each(function() // finds elements in the dom with parent element 'dog' and it's child element 'collies'
{
$(this) // 'this' would represent 'collies' element
.closest('.dogs') // .closest('.dogs') would get it's nearest occurence in the heirarchy ( basically it's parent )
.append($('<span/>', { class: 'paw-print'})); // create a dynamic span element and append to 'this'
});
If you want to append to child( element with class 'collies')
$('.dogs .collies').each(function()
{
$(this).append($('<span/>', { class: 'paw-print'}));
});
In addition to this, you also need to set position: relative as pointed out by Rob.
Example : https://jsfiddle.net/DinoMyte/1zxn8193/1/
Might be a strange setup, but I have a number of hyperlinks on the page with the same id (yeah, I know, but it was not my choice and I cannot change that at this time plus those hyperlinks are generated dynamically).
Example:
<div id="Links">
<div class="myItem">Some text</div>
<div class="myItem">More text</div>
<div class="myItem">Even more text</div>
</div>
Now I need to attach javascript to those links dynamically (the hyperlinks are also dynamically generated). The easiest way I see is by getting all hyperlinks on the page and then check the hyperlink id to ensure I only take care of those that have id of "myLink" (I have many other hyperlinks on the page).
I thought of using getElementById but that would only grab the first element with the specified id.
am attaching javascript to those links using the following:
window.onload = function() {
var anchors = document.getElementsByTagName('a');
for(var i = 0; i < anchors.length; i++) {
var anchor = anchors[i];
if (anchor.id='myLink')
{
if (anchor.getAttribute("LinkID") != null)
{
anchor.onclick = function() {
MyFunction(this.getAttribute("LinkID"), false);
return false;
}
}
}
}
}
The above function works fine, but it creates another issue - affects the styling of other hyperlinks on the page. So I was wondering if there is a way to accomplish the same thing but without affecting other elements on the page?
This is more modern and corrects your equality test:
window.onload = function() {
var anchors = document.getElementsByTagName('a');
for(var i = 0; i < anchors.length; i++) {
if (anchor[i].id==='myLink' && anchor[i].getAttribute("LinkID") !== null)
{
anchor[i].addEventListener("click", function() {
MyFunction(this.getAttribute("LinkID"), false);
}
}
}
}
Even with your original code, I don't see anything that would interfere with styling in the code. Can you elaborate as what styling changes you were getting?
You can use an attribute selector and document.querySelector([id=<id>]) pretty reliably depending on your browser support situation: http://codepen.io/anon/pen/YwLdKj
Then, of course, loop through that result and make subsequent changes or event bindings.
If not, you could use jQuery (referenced in above code pen).
You might also use JavaScript event delegation and listen for all click events, check if the user is clicking a link with the correct id.
If a combination of tag == 'a', class == "myItem" and presence of a LinkID attribute is sufficient to identify nodes requiring a click handler they could be identified using multiple CSS selectors. If this is not possible however, a query selector not using id can create a list of nodes to be checked for id, as for example:
function callMyFunction()
{ MyFunction(this.getAttribute("LinkID"), false);
}
function addClickHandlers()
{ var list = document.querySelectorAll("a[LinkID]")
var i, node;
for( i = 0; i < list.length; ++i)
{ node = list[i];
if(node.id == "myLink")
{ node.onclick=callMyFunction;
}
}
}
See also running a selector query on descendant elements of given node if of interest.
I have an issue about getElementById.
Here is the part of the javascript code that causes a problem:
var elmt = document.getElementById("cardSlotsJoueur");
elmt.style.backgroundImage = "url('images/backcard.png')";
I wanted to modify this (Css) :
#cardSlotsJoueur div {
But it actually modifies #cardSlotsJoueur {
Could you help me to find a way to modify the first one with getElementById ?
Thanks !
If you only want to modify the first div within the element with id=cardSlotsJoueur, you can use this:
var elmt = document.getElementById("cardSlotsJoueur").getElementsByTagName("div")[0];
To target #cardSlotsJoueur div it's better to use querySelector method which would retrieve children div element of the #cardSlotsJoueur container:
var elmt = document.querySelector("#cardSlotsJoueur div");
If you expect multiple div elements under the #cardSlotsJoueur then you need to get them all first
var elmt = document.querySelectorAll("#cardSlotsJoueur div");
and then set backgroundImage to each in the for loop.
You need to find div elements within #cardSlotsJoueur:
var elmt = document.getElementById("cardSlotsJoueur");
var divs = elmt.getElementsByTagName('div');
for (var i = 0; i < divs.length; i++) {
divs[i].style.backgroundImage = "url('images/backcard.png')";
}
Probably the best way to do what you want is to use a class with the required styling and add it to the element. But as an alternative, you can add a rule to the last style sheet, e.g.
function addBackground() {
var sheets = document.styleSheets;
// If there are no style sheets, add one
if (!sheets.length) {
document.head.appendChild(document.createElement('style'));
}
// The sheets collection is live, if a new sheet was needed, it's automatically a member
sheets[sheets.length - 1].insertRule('#cardSlotsJoueur div{background-image:url("images/backcard.png")');
}
You can make it generic:
function addRule(ruleText) {
var sheets = document.styleSheets;
if (!sheets.length) {
document.head.appendChild(document.createElement('style'));
}
sheets[sheets.length - 1].insertRule(ruleText);
}
and call it like:
addRule('#cardSlotsJoueur div{background-image:url("images/backcard.png")');
I have this JSFiddle where I am trying to make it so that the items in an unordered list are visible only if the option selected in a drop down matches their class. List items may have multiple classes, but so long as at least one class matches, the item should be made visible.
The Javascript looks like this:
function showListCategories() {
var selection = document.getElementById("listDisplayer").selectedIndex;
var unHidden = document.getElementsByClassName(selection);
for (var i = 0; i < unHidden.length; i++) {
unHidden[i].style.display = 'visible';
}
};
The idea is that it gets the current selection from the drop down, creates an array based on the matching classes, then cycles through each item and sets the CSS to be hidden on each one.
However, it's not working. Can anyone tell me where I'm going wroing?
Note that I haven't yet coded the "show all" option. I think I'll probably be able to figure that out once I have this first problem solved.
In your fiddle change load script No wrap - in <head>.
Just change your function like following
function showListCategories() {
var lis = document.getElementsByTagName('li');
for (var i = 0; i < lis.length; i++) {
lis[i].style.display = 'none';
}
//above code to reset all lis if they are already shown
var selection = document.getElementById("listDisplayer").value;
lis = document.getElementsByClassName(selection);
for (var i = 0; i < lis.length; i++) {
lis[i].style.display = 'block';
}
};
and in css it should be none not hidden
.cats, .rats, .bats {
display: none;
}
If you want to show all li when showAll is selected, add all classes to all lis.
You have a few things going on. First, your fiddle is not setup correctly, if you open the console you'll see:
Uncaught ReferenceError: showListCategories is not defined
This means that the function doesn't exist at the point you attach the event or that the function is out of scope, because by default jsFiddle will wrap your code in the onLoad event. To fix it you need to load the script as No wrap - in <body>.
Second, there's no such thing as a display:visible property in CSS. The property you want to toggle is display:none and display:list-item, as this is the default style of <li> elements.
Now, to make this work, it is easier if you add a common class to all items, let's say item, that way you can hide them all, and just show the one you want by checking if it has a certain class, as opposed to querying the DOM many times. You should cache your selectors, it is not necessary to query every time you call the function:
var select = document.getElementById('listDisplayer');
var items = document.getElementsByClassName('item');
function showListCategories() {
var selection = select.options[select.selectedIndex].value;
for (var i=0; i<items.length; i++) {
if (items[i].className.indexOf(selection) > -1) {
items[i].style.display = 'list-item';
} else {
items[i].style.display = 'none';
}
}
}
Demo: http://jsfiddle.net/E2DKh/28/
First there is no property in Css like display:hidden; it should be display: none;
here is the solution please not that i am doing it by targeting id finished
Js function
var selection = document.getElementById("listDisplayer");
var list = document.getElementsByTagName('li');
selection.onchange = function () {
var value = selection.options[selection.selectedIndex].value; // to get Value
for (var i = 0; i < list.length; i++) {
if (list[i].className.indexOf(value) > -1) {
list[i].style.display = "list-item";
} else {
list[i].style.display = "none"
}
}
}
css Code
.cats, .rats, .bats {
display: none;
}
JSFIDDLE
You have many things wrong in your code and a wrong setting in the jsFiddle. Here's a working version that also implements the "all" option:
Working demo: http://jsfiddle.net/jfriend00/5Efc5/
function applyToList(list, fn) {
for (var i = 0; i < list.length; i++) {
fn(list[i], list);
}
}
function hide(list) {
applyToList(list, function(item) {
item.style.display = "none";
});
}
function show(list) {
applyToList(list, function(item) {
item.style.display = "block";
});
}
function showListCategories() {
var value = document.getElementById("listDisplayer").value;
var itemList = document.getElementById("itemList");
var items = itemList.getElementsByTagName("li");
if (value === "all") {
show(items);
} else {
// hide all items by default
hide(items);
show(itemList.getElementsByClassName(value));
}
}
Changes made:
You have to fetch the .value of the select to see what the value was of the option that was picked. You were using the selectedIndex which is just a number.
A common technique for displaying only a set of objects is to hide all of them, then show just the ones you want. Since the browser only does one repaint for the entire operation, this is still visually seamless.
When finding items that match your class, you should be searching only the <ul>, not the entire document. I added an id to that <ul> tag so it can be found and then searched.
To save code, I added some utility functions for operating on an HTMLCollection or nodeList.
Tests for the "all" option and shows them all if that is selected
Changed the jsFiddle to the Head option so the code is available in the global scope so the HTML can find your change handler function.
Switched style settings to "block" and "none" since "visible" is not a valid setting for style.display.
I'm trying to replace one div with another and turn the others off:
JS
function imgToSWF1() {
document.getElementById('movie-con2 movie-con3 movie-con4').style.display = 'none';
document.getElementById('movie-con').style.display = 'block';
}
function imgToSWF2() {
document.getElementById('movie-con movie-con3 movie-con4').style.display = 'none';
document.getElementById('movie-con2').style.display = 'block';
}
function imgToSWF3() {
document.getElementById('movie-con movie-con2 movie-con4').style.display = 'none';
document.getElementById('movie-con3').style.display = 'block';
}
function imgToSWF4() {
document.getElementById('movie-con movie-con2 movie-con3').style.display = 'none';
document.getElementById('movie-con4').style.display = 'block';
}
HTML
<span onmouseover="src=imgToSWF1();"><div class="numbers">01</div></span>
<span onmouseover="src=imgToSWF2();"><div class="numbers">02</div></span>
<span onmouseover="src=imgToSWF3();"><div class="numbers">03</div></span>
<span onmouseover="src=imgToSWF4();"><div class="numbers">04</div></span>
I can't seem to get this to work and I believe that targetting multiple ID's isn't possible like this? Anyway any advice would be smashing - thanks!
You're correct that you cannot supply multiple ids to document.getElementById(). Instead, you can grab them all individually using an array. There are many ways to accomplish what you are trying to do. This is a straightforward method based on iterating through the array of the elements to hide and hiding all of them.
This method expects you to define the array of nodes to hide in each of your functions, and so is non-ideal.
// Example:
function imgToSWF1() {
var nodes = ['movie-con2', 'movie-con3', 'movie-con4'];
// Loop over and hide every node in the array
for (var i=0; i<nodes.length; i++) {
document.getElementById(nodes[i]).style.display = 'none';
}
document.getElementById('movie-con').style.display = 'block';
}
Better:
This can be refactored into one function, however. Make one function which recieves the node you want to show as an argument. Hide the others. The array should contain all nodes that may be hidden in any circumstance, and be defined at a higher scope than the function.
// Array holds all nodes ids
var nodes = ['movie-con', 'movie-con2', 'movie-con3', 'movie-con4'];
// Function receives a node id which will be shown
function imageToSWF(nodeId) {
// Loop over and hide every node in the array
for (var i=0; i<nodes.length; i++) {
document.getElementById(nodes[i]).style.display = 'none';
}
// And unhide/show the one you want, passed as an argument
document.getElementById(nodeId).style.display = 'block';
}
Call as:
<span onmouseover="imageToSWF('movie-con');"><div class="numbers">01</div></span>
<span onmouseover="imageToSWF('movie-con2');"><div class="numbers">02</div></span>
<span onmouseover="imageToSWF('movie-con3');"><div class="numbers">03</div></span>
<span onmouseover="imageToSWF('movie-con4');"><div class="numbers">04</div></span>
You have to target one element at a time with document.getElementById, eg. document.getElementById('movie-con2').style.display='none'; document.getElementById('movie-con3').style.display='none';
etc, etc.
You could also use Jquery siblings selector to show or hide all elements that are siblings within a parent tag.
You definitely can't do that in straight up javascript. The document.getElementById function only returns a single element from the DOM.
Some docs can be had here:
http://www.w3schools.com/jsref/met_doc_getelementbyid.asp
https://developer.mozilla.org/en-US/docs/DOM/document.getElementById
If you were to use a toolkit like jQuery you could do something like:
$('div[id^="movie-con"]').hide(); // hide everything
$('div["movie-con"' + index + "]").show(); // show the one we want
Since you're not using jQuery it's not quite as easy. Something like:
var matches = document.getElementById("containerDiv").getElementsByTagName("img");
for( var i = 0; i < matches.length; i++ )
matches[i].style.display = "none";
document.getElementById('movie-con' + index).style.display = "block";