Using parent() in a for loop - javascript

I am creating a chrome extension that blocks all porn results on all torrent search engine sites.
So I am trying to retrieve the name of the torrents and check them against the array of strings containing blocked (adult/porn) words that I created. If it matches the array word then it should set the display of the parent element to none. But parent() from jQuery doesn't seem to work around this in a for loop. This is the code that I am using.
// 'blockedWords' is the array.
// '$("dl dt")' contains the words that I am checking against strings from
// the array 'blockedWords'.
for (var i = 0; i < $("dl dt").length; i++) {
for (var j = 0; j < blockedWords.length; j++) {
if($("dl dt")[i].innerText.indexOf(blockedWords[j]) > -1){
$(this).parent().style.display= "none"; // 1st Method or
$("dl dt")[i].parent().style.display= "none"; // 2nd Method
// 1st Method shows the error 'Cannot set property 'display' of undefined'
// 2nd Method shows the error '$(...)[i].parent is not a function'
// '$("dl dt")[i].parent().style.display' doesn't work but
// '$("dl dt").parent().style.display' doesn't work either
// '$("dl dt")[i].style.display' works perfectly without parent().
I have also tried 'parents()'.
Any help will be appreciated :).
As a newbie, I am also open to any other suggestions or recommendations.
And I would be really grateful if you could explain your code as well :)
And by the way, can you believe there are more than 500 porn companies out there :o :P :D

Since you have jQuery, you can avoid using nested for-loops using jQuery's filter() and JavaScript reduce(s,v):
// Filter function removes elements that return a false/falsey value like 0
$("dl dt").filter(function() {
// Save current element's innerText so we can use it within the reduce function
var str = $(this).text();
// Return sum of reduce function
return blockedWords.reduce(function(s, v) {
// For each item in blockedWords array, check whether it exists in the string. Add to total number of matches.
return s + !!~str.indexOf(v);
}, 0); // 0 = intial value of reduce function (number of matches)
}).parent().hide(); // Hide elements which pass through the filter function
var blockedWords = [
'shit', 'fuck', 'sex'
$("dl dt").filter(function() {
var str = $(this).text();
return blockedWords.reduce(function(s, v) {
return s + !!~str.indexOf(v);
}, 0);
<script src=""></script>
<dl><dt>this is shit</dt></dl>
<dl><dt>this is okay</dt></dl>
<dl><dt>fuck this</dt></dl>
<dl><dt>no problem</dt></dl>
<dl><dt>sex videos</dt></dl>
EDIT: I apologize for the earlier answer if you saw it, as it was incomplete. I have also added a snippet for demonstration purposes. For further explanation of the reduce algorithm, check this answer out (basically it converts the value of indexOf to either a 0 or 1, because indexOf returns -1 if not found, or another 0-indexed integer of the position if found).

JQuery's parent function returns a JQuery object with the parent element inside of it. If you want to access the element from this object you need to retrieve the element from the object using the bracket notation.
If you were to provide some HTML I would be able to test this and make sure it works, but here is some code that could get you pointed in the right direction to use mostly JQuery instead of relying on for loops with JavaScript.
JQuery Rewrite
$("dl dt").each(function(index, element){
if($.inArray(blockedWords,$(element).text()) > -1) {
$(this).parent().css("display", "block");
$(element).parent().css("display", "block");
The Answer To Your Specific Question
Change this:
$(this).parent().style.display= "none"; // 1st Method or
$("dl dt")[i].parent().style.display= "none"; // 2nd Method
to this:
$(this).parent()[0].style.display= "none"; // 1st Method or
$($("dl dt")[i]).parent()[0].style.display= "none"; // 2nd Method
optionally, you can instead use JQuery's css function like this:
$(this).parent().css("display", "none"); // 1st Method or
$($("dl dt")[i]).parent().css("display","none"); // 2nd Method


Two blocks in getElementById [duplicate]

doStuff(document.getElementById("myCircle1" "myCircle2" "myCircle3" "myCircle4"));
This doesn't work, so do I need a comma or semi-colon to make this work?
document.getElementById() only supports one name at a time and only returns a single node not an array of nodes. You have several different options:
You could implement your own function that takes multiple ids and returns multiple elements.
You could use document.querySelectorAll() that allows you to specify multiple ids in a CSS selector string .
You could put a common class names on all those nodes and use document.getElementsByClassName() with a single class name.
Examples of each option:
doStuff(document.querySelectorAll("#myCircle1, #myCircle2, #myCircle3, #myCircle4"));
// put a common class on each object
function getElementsById(ids) {
var idList = ids.split(" ");
var results = [], item;
for (var i = 0; i < idList.length; i++) {
item = document.getElementById(idList[i]);
if (item) {
doStuff(getElementsById("myCircle1 myCircle2 myCircle3 myCircle4"));
This will not work, getElementById will query only one element by time.
You can use document.querySelectorAll("#myCircle1, #myCircle2") for querying more then one element.
ES6 or newer
With the new version of the JavaScript, you can also convert the results into an array to easily transverse it.
const elementsList = document.querySelectorAll("#myCircle1, #myCircle2");
const elementsArray = [...elementsList];
// Now you can use cool array prototypes
elementsArray.forEach(element => {
How to query a list of IDs in ES6
Another easy way if you have an array of IDs is to use the language to build your query, example:
const ids = ['myCircle1', 'myCircle2', 'myCircle3'];
const elements = document.querySelectorAll( => `#${id}`).join(', '));
No, it won't work.
document.getElementById() method accepts only one argument.
However, you may always set classes to the elements and use getElementsByClassName() instead. Another option for modern browsers is to use querySelectorAll() method:
document.querySelectorAll("#myCircle1, #myCircle2, #myCircle3, #myCircle4");
I suggest using ES5 array methods:
["myCircle1","myCircle2","myCircle3","myCircle4"] // Array of IDs
.map(document.getElementById, document) // Array of elements
Then doStuff will be called once for each element, and will receive 3 arguments: the element, the index of the element inside the array of elements, and the array of elements.
getElementByID is exactly that - get an element by id.
Maybe you want to give those elements a circle class and getElementsByClassName
document.getElementById() only takes one argument. You can give them a class name and use getElementsByClassName() .
Dunno if something like this works in js, in PHP and Python which i use quite often it is possible.
Maybe just use for loop like:
function doStuff(){
for(i=1; i<=4; i++){
var i = document.getElementById("myCiricle"+i);
Vulgo has the right idea on this thread. I believe his solution is the easiest of the bunch, although his answer could have been a little more in-depth. Here is something that worked for me. I have provided an example.
<h1 id="hello1">Hello World</h1>
<h2 id="hello2">Random</h2>
<button id="click">Click To Hide</button>
document.getElementById('click').addEventListener('click', function(){
function doStuff() {
for(var i=1; i<=2; i++){
var el = document.getElementById("hello" + i); = 'none';
Obviously just change the integers in the for loop to account for however many elements you are targeting, which in this example was 2.
The best way to do it, is to define a function, and pass it a parameter of the ID's name that you want to grab from the DOM, then every time you want to grab an ID and store it inside an array, then you can call the function
<p id="testing">Demo test!</p>
function grabbingId(element){
var storeId = document.getElementById(element);
return storeId;
grabbingId("testing").syle.color = "red";
You can use something like this whit array and for loop.
<p id='fisrt'>??????</p>
<p id='second'>??????</p>
<p id='third'>??????</p>
<p id='forth'>??????</p>
<p id='fifth'>??????</p>
<button id="change" onclick="changeColor()">color red</button>
var ids = ['fisrt','second','third','forth','fifth'];
function changeColor() {
for (var i = 0; i < ids.length; i++) {
For me worked flawles something like this
document.getElementById("myCircle1") ,
document.getElementById("myCircle2") ,
document.getElementById("myCircle3") ,
Use jQuery or similar to get access to the collection of elements in only one sentence. Of course, you need to put something like this in your html's "head" section:
<script type='text/javascript' src='url/to/my/jquery.1.xx.yy.js' ...>
So here is the magic:
.- First of all let's supose that you have some divs with IDs as you wrote, i.e.,
...some html...
<div id='MyCircle1'>some_inner_html_tags</div>
...more html...
<div id='MyCircle2'>more_html_tags_here</div>
<div id='MyCircleN'>more_and_more_tags_again</div>
.- With this 'spell' jQuery will return a collection of objects representing all div elements with IDs containing the entire string "myCircle" anywhere:
This is all! Note that you get rid of details like the numeric suffix, that you can manipulate all the divs in a single sentence, animate them... Voilá!
Prove this in your browser's script console (press F12) right now!
As stated by jfriend00,
document.getElementById() only supports one name at a time and only returns a single node not an array of nodes.
However, here's some example code I created which you can give one or a comma separated list of id's. It will give you one or many elements in an array. If there are any errors, it will return an array with an Error as the only entry.
function safelyGetElementsByIds(ids){
if(typeof ids !== 'string') return new Error('ids must be a comma seperated string of ids or a single id string');
ids = ids.split(",");
let elements = [];
for(let i=0, len = ids.length; i<len; i++){
const currId = ids[i];
const currElement = (document.getElementById(currId) || new Error(currId + ' is not an HTML Element'));
if(currElement instanceof Error) return [currElement];
return elements;
safelyGetElementsByIds('realId1'); //returns [<HTML Element>]
safelyGetElementsByIds('fakeId1'); //returns [Error : fakeId1 is not an HTML Element]
safelyGetElementsByIds('realId1', 'realId2', 'realId3'); //returns [<HTML Element>,<HTML Element>,<HTML Element>]
safelyGetElementsByIds('realId1', 'realId2', 'fakeId3'); //returns [Error : fakeId3 is not an HTML Element]
If, like me, you want to create an or-like construction, where either of the elements is available on the page, you could use querySelector. querySelector tries locating the first id in the list, and if it can't be found continues to the next until it finds an element.
The difference with querySelectorAll is that it only finds a single element, so looping is not necessary.
document.querySelector('#myCircle1, #myCircle2, #myCircle3, #myCircle4');
here is the solution
if (
document.getElementById('73536573').value != '' &&
document.getElementById('1081743273').value != '' &&
document.getElementById('357118391').value != '' &&
document.getElementById('1238321094').value != '' &&
document.getElementById('1118122010').value != ''
) {
You can do it with document.getElementByID Here is how.
function dostuff (var here) {
if(add statment here) {
document.getElementById('First ID'));
document.getElementById('Second ID'));
There you go! xD

Detect a button and then press it in JavaScript

I want to make a function that would detect a button on a web page and then click it. But I want it to click a specific item.
function imready()
var btn = document.getElementsByClassName('text-xxxs mb-02');
for (var i = 0; i < btn.length; i++)
if (btn[i].innerText.indexOf('AK-47') > -1)
chrome.runtime.sendMessage({ type: 'dontrun', update: 1 }, function (response) {
How do I make it so that the var "btn" should equal to document.getElementsbyClassName('x') and also a different className ('y')?
Quoting from
getElementsByClassName() returns an HTMLcollection object which is similar to an array but not really an array so you can't call
array methods using the returned value. One hack is to use Array's
prototype methods along with .call()/.apply() to pass the returned
object as the context.
var elems = document.getElementsByClassName("royal") ;
var collapsedElems = document.getElementsByClassName("collapsed");
var earray =, 0);
var concatenated = earray.concat.apply(earray, collapsedElems) ;
Demo Fiddle
As far as i understand your question, you can use document.querySelector('.classX.classY') to select the needed button with both classes.
That works for the case if you only need one button on the page selected, from your code i assume exactly that.

How to compare if an HTML element exists in the node array?

selectedContentWrap: HTML nodes.
htmlVarTag: is an string.
How do I check if the HTML element exists in the nodes?
The htmlVarTag is a string and don't understand how to convert it so it check again if there is a tag like that so that if there is I can remove it?
here is output of my nodes that is stored in selectedContentWrap
var checkingElement = $scope.checkIfHTMLinside(selectedContentWrap,htmlVarTag );
$scope.checkIfHTMLinside = function(selectedContentWrap,htmlVarTag){
var node = htmlVarTag.parentNode;
while (node != null) {
if (node == selectedContentWrap) {
return true;
node = node.parentNode;
return false;
Well if you could paste the content of selectedContentWrap I would be able to test this code, but I think this would work
// Code goes here
var checkIfHTMLinside = function(selectedContentWrap,htmlVarTag){
for (item of selectedContentWrap) {
if (item.nodeName.toLowerCase() == htmlVarTag.toLowerCase()){
return true;
return false;
Simplest is use angular.element which is a subset of jQuery compatible methods
$scope.checkIfHTMLinside = function(selectedContentWrap,htmlVarTag){
// use filter() on array and return filtered array length as boolean
return selectedContentWrap.filter(function(str){
// return length of tag collection found as boolean
return angular.element('<div>').append(str).find(htmlVarTag).length
Still not 100% clear if objective is only to look for a specific tag or any tags (ie differentiate from text only)
Or as casually mentioned to actually remove the tag
If you want to remove the tag it's not clear if you simply want to unwrap it or remove it's content also ... both easily achieved using angular.element
Try using: node.innerHTML and checking against that
is it me or post a question on stackoverflow and 20min after test testing I figure it.,...
the answer is that in the selectedContentWrap I already got list of nodes, all I need to do i compare , so a simple if for loop will fit.
To compare the names I just need to use .nodeName as that works cross browser ( correct me if I am wrong)
Some dev say that "dictionary of tag names and anonymous closures instead" - but couldn't find anything. If anyone has this library could you please post it to the question?
here is my code.
var node = selectedContentWrap;
console.log('node that is selectedwrapper', selectedContentWrap)
for (var i = 0; i < selectedContentWrap.length; i++) {
console.log('tag name is ',selectedContentWrap[i].nodeName);
var temptagname = selectedContentWrap[i].nodeName; // for debugging
if(selectedContentWrap[i].nodeName == 'B' ){
console.log('contains element B');

jQuery's .add on an empty set?

I am working on a plugin with quite a few options and as a consequence I am trying to keep track of a set of elements and put them in a variable. The variable cannot be empty (but that is of no concern here). Let's say there are only two options, then the variable will hold one or two elements as a jQuery object, i.e. $("#el1, #el2"). I tried the following, but the result of adding is still $([]).
var track = $([]);
someFunc() {
if (option1) track.add("#el1");
if (option2) track.add("#el2");
// result is `$([])`
Note that I don't want an array back, but a jQuery selector as I posted in the example above.
You could first sort out which elements/selectors you need.
And then use these to init the track variable with an jQuery object passing in all the relevant selectors.
var track = someFunc();
// you would have to check the length of `track` first as it may be only an empty array (length == 0) and no real jQuery object
if (track.length) {
// returns a jQuery object with all the matched elements
// or an empty array if there is no relevant selector
function someFunc() {
// place to store the selectors
var selectors = [];
// store the relevant selectors in <selectors>
if (option1) selectors.push("#el1");
if (option2) selectors.push("#el2");
// if there is at least one selector in <selectors>
if (selectors.length > 0) {
// create a jQuery object of them and return it
return $(selectors.join())
} else {
// otherwise we return an empty array
// this allows us to use .length in both cases
return [];
// or always return a jQuery object
// return $(selectors.join());
Use a array join on coma:
var elements = [];

Is it possible to get element's numerical index in its parent node without looping?

Normally I'm doing it this way:
for(i=0;i<elem.parentNode.length;i++) {
if (elem.parentNode[i] == elem) //.... etc.. etc...
function getChildIndex(node) {
return, node);
This seems to work in Opera 11, Firefox 4, Chromium 10. Other browsers untested. It will throw TypeError if node has no parent (add a check for node.parentNode !== undefined if you care about that case).
Of course, Array.prototype.indexOf does still loop, just within the function call. It's impossible to do this without looping.
Note: If you want to obtain the index of a child Element, you can modify the function above by changing childNodes to children.
function getChildElementIndex(node) {
return, node);
Option #1
You can use the Array.from() method to convert an HTMLCollection of elements to an array. From there, you can use the native .indexOf() method in order to get the index:
function getElementIndex (element) {
return Array.from(element.parentNode.children).indexOf(element);
If you want the node index (as oppose to the element's index), then replace the children property with the childNodes property:
function getNodeIndex (element) {
return Array.from(element.parentNode.childNodes).indexOf(element);
Option #2
You can use the .call() method to invoke the array type's native .indexOf() method. This is how the .index() method is implemented in jQuery if you look at the source code.
function getElementIndex(element) {
return [], element);
Likewise, using the childNodes property in place of the children property:
function getNodeIndex (element) {
return [], element);
Option #3
You can also use the spread operator:
function getElementIndex (element) {
return [...element.parentNode.children].indexOf(element);
function getNodeIndex (element) {
return [...element.parentNode.childNodes].indexOf(element);
You could count siblings...
The childNodes list includes text and element nodes-
function whichChild(elem){
var i= 0;
while((elem=elem.previousSibling)!=null) ++i;
return i;
There is no way to get the index of a node within its parent without looping in some manner, be that a for-loop, an Array method like indexOf or forEach, or something else. An index-of operation in the DOM is linear-time, not constant-time.
More generally, if list mutations are possible (and the DOM certainly supports mutation), it's generally impossible to provide an index-of operation that runs in constant time. There are two common implementation tactics: linked lists (usually doubly) and arrays. Finding an index using a linked list requires a walk. Finding an index using an array requires a scan. Some engines will cache indexes to reduce time needed to compute node.childNodes[i], but this won't help you if you're searching for a node. Not asking the question is the best policy.
I think you've got it, but:
make sure that variable "i" is declared with var
use === instead of == in the comparison
If you have a collection input elements with the same name (like <textarea name="text_field[]"…) in your form and you want to get the exact numeric index of the field that triggered an event:
function getElementIdxFromName(elem, parent) {
var elms = parent[];
var i = 0;
if (elms.length === undefined) // there is only one element with this name in the document
return 0;
while((elem!=elms[i])) i++;
return i;
Getting numeric id of an element from a collection of elements with the same class name:
function getElementIdxFromClass(elem, cl) {
var elems = document.getElementsByClassName(cl);
var i = 0;
if (elems.length > 0) {
while((elem!=elems[i])) i++;
return i;
return 0;
Try this:
let element = document.getElementById("your-element-id");
let indexInParent =;