Document queryselector returns null.

Document queryselector returns null TypeScript is fore-warning you about this possibility. Essentially, if for whatever reason no element in your DOM matches that selector query (. As a front-end developer with 5 years of experience, you may have encountered a weird situation when working with the document. selector') is null or not. box'); Instead, you should move the JS script tag to the bottom of the body, after the elements it tries to access. I can't figure out why it behaves like this. getElementsByClassName() to check if an element with a given class exists. Ask Question Asked 4 years, 9 months ago. querySelector(#${YOU['div']}) Mar 20, 2025 · Document. log(document. backgroundColor = 'white'; Jun 19, 2024 · Solving Null Property Issues with document. getElementById() returns NULL in ReactThe document. querySelector method is ubiquitious in JavaScript but somewhat tricky to type in a safe way. If the page doesn’t have any element with the id save, the document. querySelectorメソッドの戻り値がnullかどうかをチェックすることで、要素が見つからない場合の処理を適切に行うことができます。 document. If no element with the provided selector exists in the DOM, the method returns a null value. The title should give a proper summary of the actual problem and not a "might describe the situation good enough" – Sep 6, 2021 · If you want to detect when an element appears then you need to either: Listen for mutations to the DOM; Poll (e. email"); 它将返回具有’class’属性为’email’的第一个输入元素。 Oct 1, 2021 · JSでDOMを取得する際に使用するquerySlectorやgetElementByIdなど。とても便利だけど、読み込み順番を間違えると「null」つまり「無いよ」と言われてしまいます。今回はそんなDOM取得の際の読み込み順番についての解決策についてのお話です。 Oct 5, 2023 · I'd like something as elegant as document. querySelector('main'), and line becomes const mainElement = document. — You are receiving this because you are subscribed to this thread. Obviously attaching the event to null instance fails and results in Sep 26, 2018 · You are trying to get element pausebuttons with query selector but that is null. The matching is done using depth-first pre-order traversal of the document's nodes starting with the first element in the document's markup and iterating Both are array-like collections (lists) of nodes (elements) extracted from a document. querySelectorAll("tabbable") is looking for an element of the tag <tabbable>. querySelector('#save'). 1. Apr 15, 2016 · The way you're using it, document. $$() to obtain an ElementHandle array: let list = await page. querySelector in JavaScript. Jul 22, 2020 · componentDidMount() { var element = document. build the aforementioned automatic return mechanism). var el = document. Besides the querySelector(), you can use the querySelectorAll() method to select all elements that match a CSS selector or a group of CSS selectors: Dec 5, 2014 · Per the answer by @AmitJoki, the line var elem = document. document. If you're not using strictNullChecks then Element, and it doesn't have the value member. getElementById ('container'); console. However, if I use document. But i have some specific requirements like having a fixed text in the middle of a donut chart so i have to position the chart absolutely, since it's rendered as a canvas, so i have to set the size of the wrapper div manually. Mar 16, 2018 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. So how should we prevent errors with querySelectorAll?Previously I would use instanceof to check if my variable was a NodeList, but this doesn’t work because querySelectorAll always returns a NodeList. head. contentWindow. Jul 27, 2020 · The DOM's document. manifest. I have also tried to use DOMContentLoaded in order to execute my code after the DOM has been loaded since I suspect this is a DOM issue. Modified 2 years, 10 months ago. This article will discuss the common issue of null properties and provide solutions to help you overcome this you have a few options: Mess with the // @run-at script setting to try to run later (not guaranteed to work consistently. querySelector('SVG > a:nth-child(2) > text'). querySelector("canvas"); is getting the element from tag name canvas. I tried chaining them together but still I eventuall May 28, 2022 · Ran into a problem that querySelector() returns null for an element that exists on the page. Aug 19, 2019 · tableBody = document. Jul 12, 2022 · document. Provide details and share your research! But avoid …. querySelector<E extends Element = Element>(selectors: string): E | null; This is a mismatch for both, to fix this, you will need to cast the return object from querySelector. my-element')); Dec 24, 2016 · I use the following code to dynamically create an iframe. getElementById('. Then we make sure that the input element is already loaded by putting the document. However, anytime I try to store the divs with a class of . contentDocument. querySelector返回null但元素存在. textContent;. textContent of null, that'll throw an exception. querySelector("button") null > container. supplier-data'); } Then in the render method I call another file which calls another file which calls another file which has the following in its render method: I'm trying to build a chrome extension for Vimeo but I don't understand why document. log('init', iframe. querySelector() 方法返回 null 的情况. If no matches are found, null is returned. And so casting it to HTMLInputElement as I wrote in my comment works: let myRow = document. href, should be var elem = document. (source: MDN) This method is a part of the Document interface. querySelector HTML document. I want to track changes to an element on a page using MutationObserver, but I get null when trying to find the element I need. NodeList is always empty when running querySelectorAll() 2. The issue is that you are attempting to access a property of a null value (null. selector'); Oct 31, 2020 · But if I choose container instead of the main element (this is the first child element of the main element) in the 3rd code line const mainElement = document. In Firefox this returns a NULL. Since it looks like you're trying to query by a class, add the period to denote it is such. querySelector returns only the first element that matches the given selector, while querySelectorAll returns a NodeList of all the elements matching the selector. querySelector always returns null. Mar 3, 2024 · const el = document. E. Feb 3, 2021 · Alternatively if you know from the context of your program that this query will not return null, you can use a TypeScript non-null assertion (!): document. log still returns null so I'm a bit puzzled. This attribute is read-only. price'); should be return document. querySelector method in React. Jun 7, 2021 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand Feb 20, 2022 · ts中document. com. Aug 7, 2019 · `[]. offsetWidth In google chrome this returns the width of a the text element which is nested inside an a (anchor) element which is nested inside an svg element, as is expected. A common issue when using document. Aug 14, 2013 · I'm using the waitForSelector() and captureSelector() methods in CasperJS to wait for and select an element using a CSS selector, then save a screenshot of it. Related questions. select')`の結果がnullとなりますが、何か誤りがありま Jan 1, 2022 · The CSS id selector uses the ID attribute of an HTML element to select one unique element on a page. 0 Can't get selenium to find element and select it. Viewed 704 times -1 . Apr 7, 2022 · To put it as simply as we can, querySelector is a method for finding elements on any website. If no element matches the CSS selectors, the querySelector() returns null. Jan 5, 2017 · document. value = " a vaule"; Aug 30, 2021 · let selects = document. What's going on? var x = document. The index starts at 0. querySelector works but querySelectorAll doesn't-1. It does not work at all for this particular page under test (always returns null). querySelector() returns null. js environment because they are separate. querySelector() 方法查询元素时，有一些情况会返回 null。以下是一些可能导致返回 null 的情况：选择器没有匹配的元素：如果使用的选择器在文档中没有匹配的元素，那么 document. Wait for some meaningful event. $$('. The Document method querySelector returns the first Element within the document that matches the specified selector, or group of selectors. querySelector() 方法将返回 null。 Oct 3, 2023 · document. Use page. querySelectorAll([css selector]). Feb 14, 2024 · Handling Null Values. querySelector('#your-box')) In this case, you can use the backticks: document. I'm already despera Aug 2, 2021 · The querySelector method returns Element | null. querySelector(". styleSheet = document. I. getElementById('#hello') // will return null 尽管将document. href). Oct 30, 2019 · querySelector() の場合には戻り値がnullなのでこれでいいのですが、querySelectorAll() を使った時にほんの少しハマったので共有しておきます。 Chrome Developer Tool のコンソールで動作を確認してみます。 querySelector() のケース May 30, 2021 · Preventing Errors with document. queryselector returns null value. e. querySelectorAll ('div. Sep 28, 2020 · Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Jun 30, 2018 · The contentWindow property returns the Window object generated by an iframe element (through the window object, you can access the document object and then any one of the document's elements). getElementById('my-row'); (myRow. Return value. Returns null if no matches are found; otherwise, it returns the first matching element. Mar 27, 2024 · To overcome the problem of querySelector returning null, you can follow these solutions: Check if the element exists. You can't access class by doing something like. querySelector returns null on lines 37 and 38 (I've marked these lines in the code so you don't have to look for them), when pressed for the first time, and then returns the desired value I was facing the same problem and now it is resolved by using var canvas=document. textContent = styles document. querySelector is returning null is that the DOM does not contain that element yet. . Gostaria que alguém pudesse me explicar o porque disto estar acontecendo, e me dar uma dica de como solucionar este problema. querySelectorAll returns null for any inquiry. After clicking button, alert is not showing up. The event handler is not successfully attached to the button, and if you dig in the console you’ll see an error: TypeError: elem is null. The Document method querySelector() returns the first Element within the document that matches the specified selector, or group of selectors. querySelector("canvas"); instead of var canvas=document. May 25, 2020 · document. appendChild(styleSheet) const element = document. Not sure if this doesn't work with polymer (no reason it shouldn't) or I haven't imported something or what else is wrong. So to select those you Apr 2, 2020 · Unfortunately, querySelector always returns null no matter what selector I pass to it. Asking for help, clarification, or responding to other answers. querySelector报错如何处理呢？感谢！ ParentNode. ). querySelectorとquerySelectorAllの違い Nov 21, 2019 · document. forEach. querySelector("input. getElementById() method returns null in React when we call the method before the element with the provided ID has been rendered to the DOM or if an element with the ID doesn't exist. title'); Dec 12, 2020 · The callback passed to page. The current page I'm seeing this problem with is www. e. style. You can't return DOM nodes back to Puppeteer--it must be serializable data. querySelector('link[rel="service"]'),. querySelector('. Nov 9, 2023 · With React, like a lot of frameworks, the idea is to get people away from thinking about the DOM and thinking more about their data/state. querySelector返回null。以下是我的HTML： Sep 1, 2021 · Meanwhile, document. VueJS test-utils can't find element inside child component. call`の挙動について学習中ですが、以下のコードで `document. # [Solved]: document. querySelector tutorial shows how to use querySelector to select HTML elements in JavaScript. addClass("foo") . The nodes can be accessed by index numbers. May 17, 2024 · このように、document. querySelector('[data-testid="AddToCartButton"]') null > container. js environment. 5. querySelector does not return this one particular element. querySelector(), it returns nothing (technically, it returns null), because there is no element to find (yet)! This test page on JSFiddle shows this. An HTMLCollection is a collection of document elements. evaluate runs in the emulated page context, not in the standard scope of the Node script. Apr 9, 2021 · On this page and in the videos I watched, everything worked and returned <h1> Hello </h1>. Aug 13, 2021 · We add the event handler with the document. querySelectorAll(). QuerySelector returns null from a name given in javascript array. I've tried using the selectors *, form, and form#mini_search_form for this page and all return null. querySelector() Method: The querySelector() method returns the first element within the document which matches a specified Oct 12, 2017 · I use the querySelector in JS to select html markup that I filled in with a JS script. appendTo(container); // container is a jQuery object Jun 25, 2019 · TypeScript is warning you that el. However, I'm finding that because the css background has been set to transparent, the screenshot turns out pretty ugly, so I'd like to set the background to white. querySelectorAll('input[type=checkbox]'); Note that radio buttons <input type="radio"> and check boxes <input type="checkbox"> are both input tags with a different `type attribute. NEAR { display:block; } ` window. Please note that the querySelector() method returns a single matching element, whereas the querySelectorAll() method returns a list of all matching elements. # Check if a DOM element exists using getElementsByClassName. Suggested solution: Fix it somehow, but I'm not sure why it's not working. Before using the querySelector method, ensure that the element exists in the HTML document. Part of that, for React especially, is the performance benefits that can be had when you let the library figure out the delta that needs to happen between one state and another. hello') // will return null Also, note that you don't need to pass # in this function argument. querySelectorAll('select'); let radioInputs = document. querySelector("div. querySelectorAll returns a static Apr 7, 2024 · You can also use the document. 0 Selenium WebDriver Unable to Find Element by Id, Using Nov 11, 2020 · The querySelector returns null on the marked line while when using select by a class (like on the next line) it works fine. main input[name='login']"); Notes. querySelector('container') i get this error: error Jul 31, 2017 · **UPDATED ** with a solution that comes close to working: I'm trying to get my 'skip to content' link to jump to the first focusable element after '#content-start'. You can use this Window object to access the iframe's document and its internal DOM. with querySelector in a recursive setTimeout or a setInterval) the DOM using querySelector until it does appear (i. May 8, 2016 · This solution does the following: Uses the ES6 spread operator to convert the NodeList of all divs to an array. querySelector. Oct 17, 2013 · A current issue I'm having is that for some webpages I try to scrape, for some reason, getElementsInfo, and evaluate document. card in the const questionCard, I get null. For instance, I tried the following in the live debugger: > container. body and directly to the Apr 10, 2014 · The first statement contains a bool value depends on document. querySelector() 将返回与指定的选择器组匹配的第一个元素。如果没有找到匹配项，则返回“null”。语法： let input = document. Oct 29, 2020 · document. querySelector call inside the DOMContentLoaded event handler. If we have to access any element-specific properties on the variable, we have to use a type assertion to type it correctly Jun 15, 2023 · I'm following Kevin Powell's tutorial on creating a responsive navbar when I encountered this problem. , document. If the selector matches an ID and this ID is erroneously used several times in the document, it returns the first matching element. log (el); // 👉️ null // ⛔️ Cannot read properties of null (reading 'querySelectorAll') el. some-class') may return null. querySelector() 方法时，如果没有匹配的元素，则返回 null。这通常出现在以下情况：选择器没有匹配的元素. Apr 13, 2018 · vue-test-utils returns null for document. Expressions can't be passed between the page and the Node script without careful considerations: most importantly, if something isn't serializable (converted into plain JSON), it can't be transferred. querySelector returns null until element is inspected using DevTools, however there are some significant differences that are quite confusing and suggest that the problem may be different. querySelector() returns null in my code but works fine if I type it in the chrome inspector. Não estou conseguindo identificar o porque deste erro estar acontecendo nem como resolvê-lo. Here is the HTML for the example. querySelector('#my-paragraph') selects the first element with the ID my-paragraph. Apr 20, 2022 · I want to call a function when a button within an iframe is clicked, but I am already having problems accessing the iframe document. readyState); console. wrap your code in a addEventListener('load', => { /* your code */ });, but if the site is constructing the page dynamically after load, it won't help. getElementById("canvas");. You can also use the document. user-panel. I looked up stackover flow for some answers, I tried: waitForSelector() & page. querySelectorAll #. 当使用 document. First, I followed this video, but null is returned when the func Jul 27, 2022 · Document. selector'); var selection = document. createElement("style") styleSheet. Console. querySelector on the "sign-in-box" returns null. querySelector("div") null I'm clearly doing something spectacularly wrong. querySelector in a window. Provides output if the div contains the query string, not just if it exactly equals the query string (which happens for some of the other answers). However, Chrome still returns null. json file: "manifest_version": 2, Jun 3, 2018 · This doesn't work--return document. Aug 9, 2024 · I have issues selecting certain elements on a specific web page, querySelector returns null unless I first go through one of the parent element. querySelector<HTMLElement>('. document. let classList = document. 2. some-class), you'll get null back. The problem is that you are using document. – Jul 9, 2020 · document. Here you are getting null so no matches found with this selector. querySelectorAll, which returns an iterable NodeList (or null) that does not require testing on the returned data before performing work on it. querySelector() 方法将返回 null。 Aug 27, 2020 · The approach I took to solve this issue is as follows: // using an IIFE ("Immediately-Invoked Function Expression"): (function() { 'use strict'; // using Arrow function syntax to define the callback function // supplied to the (later-created) mutation observer, with // two arguments (supplied automatically by that mutation // observer), the first 'mutationList' is an Array of // MutationRecord Mar 3, 2024 · To solve the "Cannot read property 'querySelector' of null" error, make sure you're using the correct `id` when selecting the DOM element. Jul 5, 2020 · In a debugger I can see that querySelector returns null regardless of the selector I used. The script setup runs when the component is created, so the component's DOM has not been created yet. querySelector(parameter); Parameters. querySelector('#test')); The reason the readyState is already complete is the iframe has a content document when it is created, well before the new content -- with the test element -- has been loaded. returns an undefined Mar 5, 2024 · If neither element is found, the querySelector() method returns null. Can anyone please help me understand why this Queryselector returns null when trying to access the div element? Feb 29, 2024 · The querySelector method has a return type of Element | null. querySelector('#overlay-root') as Element, It is a "react" library, react-chart-js-2, which seems to be chartjs with some slight adaptations to react. Aug 25, 2024 · This is my first time trying to make a Chrome extension. querySelector() with TypeScript is handling potentially null values, as the method returns null if no elements match the selector. querySelector('#b>a'); console. Then if you try to read the . querySelector return an Element OR Null. querySelector() 返回 null 的情况. setUserAgent(UserAgen document. selector') !== null; the second statement contains the actual value of document. Dec 8, 2020 · So I'm building a multi form with tabs, however when I try to log the const: const breadcrumbs = document. log(x); var y = Mar 29, 2021 · OK, so now you basically just need to add '#' to your querySelector, so it'll be looking for an element with an id 'your-box' (document. solesociety. querySelectorAll('. Googled and found out about "run_at": "document_end" and added it in my manifest file but my console. querySelector returns null. log still returns null. This post walks through how you can create a safe querySelector for use in TypeScript code and explains how this is an example of a general pattern of using values (which exist at runtime) as a source of truth, rather than types (which don't). May 2, 2023 · console. querySelector, it works as expected. querySelector放在window. Here's the corrected JavaScript code: Apr 10, 2025 · The Document method querySelector() returns the first Element within the document that matches the specified CSS selector, or group of CSS selectors. var selection = document. Dec 20, 2023 · querySelector() and querySelectorAll() are two jQuery functions which helps the HTML elements to be passed as a parameter by using CSS selectors ('id', 'class') can be selected. getElementById('hello') This is our good old way to access an id (not a class). NEAR'); But element is always null… I’ve also tried adding the style section to document. You can use the console. querySelectorAll('input[type=radio]'); let checkbox = document. It seems my 'const primary_nav = document. The difference is: var canvas=document. addEventListener("load"), my document. addEventListener method to listen to the event emitted by the html element. price'). I will be very grateful for your help. 当调用 document. nf-breadcrumbs li'); in the console it returns the correct NodeList. var iframe_jquery = $("<iframe>") . Mar 16, 2025 · Returns a single element object or null if no match is found. To use an ID selector in CSS, you write a hashtag # followed by the ID of the element but there is no need and actually very confusing and wrong to add the # in the value of the attribute. querySelector() instead of document. console. querySelector("#modelTable > tbody"); que sempre retorna null. 当指定的选择器没有匹配的元素时，document. I almost never use for loops anymore (favoring pure higher order functions and utilizing array methods like map instead), so I forget about some of the idiosyncrasies of a raw loop. May be Apr 7, 2023 · If the iframe and the iframe's parent document are Same Origin, returns a Document (that is, the active document in the inline frame's nested browsing context), else returns null. Dec 3, 2021 · Despite putting the document. Aug 29, 2024 · Therefore, when the browser executes document. querySelector is returning null for both class and id selectors. Example of contentDocument Jan 12, 2022 · My problem appears to be quite similar to this problem: Document. it returns null. Exceptions Nov 18, 2017 · Oh yes. I am currently building a May 28, 2019 · However, I realized now that I skipped important information - the problem is not that document. Aug 9, 2017 · querySelector returns null when searched for the id "#b>a", but getElementById returns the correct element. highlighted')!. An Element object or null if no element matches the selectors. querySelector('link[rel="service"]'). Both have a length property that returns the number of elements in the list (collection). forEach(function (element) { [business logic using element] }); Jan 15, 2022 · I did try it with a regular class and the Queryselector found the element, but in this project, I need to use modules. Apr 10, 2025 · The Document method querySelector() returns the first Element within the document that matches the specified CSS selector, or group of CSS selectors. classList; Code language: JavaScript (javascript) In this example, we select an element with id save and access its classList property. Here is my HTML: <!DOCTYPE html& Jul 23, 2024 · Hi, I have the following code (more or less) in a Firefox extension: var styles = ` . The matching is done using depth-first pre-order traversal of the document's nodes starting with the first element in the document's markup and iterating May 15, 2021 · "Document query selector returns undefined" (which won't ever be the case) but then "Type Error: Can not read property ClassList Of Null". Solution: You can return an ElementHandle, which is a representation of an in-page DOM element, back to the Node. addEventListener("load")中，但“登录框”上的document. primary-navigation")' returns a value of null even though the class name exists. reduce your webpage by removing bits at a time until you're either left with just that element and things still don't work, or at some point you remove something and suddenly your code does work. log() method to check the value of the querySelector method. 0. nf-breadcrumbs li'); It returns an empty NodeList, however when I use document. querySelector method in JavaScript. hence iframe. querySelector<"body">(selectors: "body"): HTMLBodyElement | null (+2 overloads) Returns the first element that is a descendant of node that matches selectors. Reproduction: Problem description: The provided documentation doesn't match what is necessary to make this work. The TypeScript compiler, especially with strict null checks enabled, will enforce proper checking of null values. myClass') as HTMLInputElement). querySelector('#save') returns null. Conditionally rendering message on HTML page from Typescript in runtime Aug 3, 2014 · For some reason document. A Sep 23, 2017 · In other words, you cannot return an element from the page DOM environment back to the Node. g. The querySelector() method is available on the document object or any Element object. Apr 4, 2022 · The reason document. Mar 29, 2017 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand myVar = document. Jan 6, 2019 · Problem: querySelector returns null on DOM element that is clearly visible: I believe that you cannot get proper value using document. Aug 26, 2024 · This is why it's important to run through the minimal reproducible example exercise: take your code, and throw away everything that isn't involved in the problem. That makes sense. A string containing one or more CSS selectors to match. ugktfi xidatk tlnz ankbvk vngdc omtkxe vpehvtpj myfpyc fwim hitg umsr feomnn elinun hcaji tpyh