Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. Thank you Chris Rivera, I concur, this is exactly what I was thinking reading this article. The nodes can be accessed by index numbers. Javascript data-attribute. classes are specifically used for styling and data attribute specifically tied to javascript functionality. According to him, this is only an issue for very large and complex sites. As we can see, both CSS and JS use the same class to get their job done. Access data attributes with data() function. The setAttribute () method adds the specified attribute to an element, and gives it the specified value. That way alterations to the dom do not interfere with the reference pointers, there is no chance of causing accidental styling derps, and the likelihood that another library is using your unique data attribute is very small. Approach 1: We can use the inbuilt setAttribute() function of JavaScript. Besides the performance issue, what bothers me more is the fact that the data attribute, by definition, is just not intended to be used that way. The advent of HTML5 introduced a new attribute known as 'data'. Especially with complex systems where backend devs build the JS for callbacks etc. Die Konvertierung in andere Datentypen (z.z. Here you can see that two type of get data attribute methods are :-.data(‘attribute’) method getAttribute oder (ab IE11) mit dataset.status behandelt. But then again, performance is always an issue and I don’t consider avoiding data attributes for selection to be premature optimization. Well, for one there are performance issues. Performance can be an issue in many or most cases, but it’s not always an issue, specially when talking about things executing on the client side (btw, I wanted to see the numbers and your link to roytomeij’s site is broken). Definition and Usage. Developer Intent Javascript takes a selector to map to a DOM element, selector being the keyword not class. In vanilla JavaScript setting a data attribute of an element is done with the generic setAttribute() method. [see DOM: Get Current Script Element] Get Element by Matching the Value of the “id” Attribute document.getElementById(id_string) Return a non-live element object. Returns null if not found. Classes can be used to select more than 1 item but leaves developers clueless how things are wired up. The Element.attributes property returns a live collection of all attribute nodes registered to the specified node. HTML-Attribute. And here’s how we get the same element by a Data Attribute using the Javascript document.querySelector function: const link = document.querySelector('[data-link="1"]'); In the above example, I used the data-link Data Attribute as the hook to grab the element in Javascript because that’s what I intended the function of that Data Attribute to be. Example: Additionally, if it’s unlikely that some other library collides with your selected unique data attribute, it would probably be equally unlikely if you picked a “likely-to-be-unique” prefix for all your own classes. How to append an element after an element using jQuery? jQuery offers various method to get data attribute values, Here You can learn two simple method to get data-any attribute of selected html Elements. The most compelling reason is that HTML is a living language and just because attributes and values that d… Could you please provide a code example to further illustrate the problem? Say you want to dynamically load a video object. In real life one should try to generalize the name of a JS component to describe its functionality, regardless of the content. Remember the W3C definition? The output will look something like this-Advertisements. document.write(new Date().getFullYear()); Get the value of the class attribute of an

element: The getAttribute() method returns the value of the attribute with the specified name, of an element. The getElementById() method returns the element that has the ID attribute with the specified value. Through this change both CSS and JS won’t work anymore. It always bugged me that dependencies between styling (CSS) and logic (JS) arise through shared classes. The most extensible selector we can use would be the Data Attribute. The developer renames the HTML class from cars to vehicles. Now, we need to select the above elements by data attribute in JavaScript. Real Example: Every attempt is made to convert the attribute's string value to a JavaScript value (this includes booleans, numbers, objects, arrays, and … The getElementsByTagName() method returns a collection of an elements's child elements with the specified tag name, as a NodeList object. Add Comment Read More. Thanks. Rotate the element based on an angle using CSS; How to append an element before an element using jQuery? This is the new link: https://roytomeij.com/en/dont-use-class-names-to-find-html-elements-with-js/, dom query selector performance is totally overrated, we have clients on 64bit 8g+ RAM, cuad-core 3ghz, they will be fine. Makes for a bit easier debugging too since you tell, at a glance, if a class is being added or was already there. Trying to decouple CSS and JS by using data attributes is not a new thing. Get code examples like "javascript get element by data attribute" instantly right from your google search results with the Grepper Chrome Extension. I dont think using the data attribute to find an element is a deviation from the w3c definition. Examples might be simplified to improve reading and learning. var $carsList = $module.find(“[data-car]”) SITEMAP . The W3C specification defines the data attribute as follows: The getAttribute () method returns the value of the attribute with the specified name, of an element. var $carsList = $(“.cars”); This is the equivalent of jQuery's $.data() method. With the introduction of HTML5, JavaScript developers have been blessed with a new customizable and highly flexible HTML tag attribute: the data attribute. I disagree … “what bothers me more is the fact that the data attribute, by definition, is just not intended to be used that way” – true but true for css classes as well. Which is also what the libraries should have done to facilitate reuse, naturally. Bootstrap uses data-attribute approach as they are a framework and cannot rely on users to use consistent IDs or class names, data-toggle=”modal” If the selector is not valid CSS syntax, the method will raise a SyntaxErrorexception. The attribute selectors provide a very powerful way to select elements. Finally, I highly disagree with your statement “performance is always an issue”. I am not yet sure what exactly you are trying to do on your page. The getElementsByClassName () method returns a collection of all elements in the document with the specified class name, as an HTMLCollection object. Hi, I was working with data- attribute and I was searching what is the best way of select html with this kind of selector. Tip: Use the getAttributeNode () method if you want to … All Javascript i write it tied to data-attributes, Now lets get down to performance. The column contains different blocks of filter, below one filter category box: I used ‘data-filter’ because I need a name reference of the filter, If I use a class I cannot create a loop and get the category name because inside the class i could use others class. I created a fund list and filtering tool. The name of the attribute you want to get the value from. The querySelector() is a method of the Element interface. This sometimes led to problems and could cause conflicts between the styling and functionality of websites. Now, how do you extract and use the data that are associated with the elements? If the attribute exists on the element, the getAttribute() returns a string that represents the value of the attribute. data-Attribute sind Zeichenketten oder Strings, die alles speichern, was in einem String stehen kann – ähnlich wie JSON. What is discouraged is making upyour own attributes, or repurposing existing attributes for unrelated functionality. We have also demostrate about the jquery set data attribute below. JavaScript getAttribute() example If we wanted to show the data to our users when they click on a list element, we could easily achieve this with some JavaScript. A more scalable and robust module could look like this: The names of the data attributes are no more associated to the content within the module. If the next developer does not know the intent or needs to read all the code previously written to understand whats going on then there is a lack of efficiency when working with Large teams of developers. I agree with this. Every HTML element may have any number of custom data attributes specified, with any value. Data Attribute is the slowest javascript selector since there are more data attributes in a DOM than ids and classes, so for performance reasons we cache the selector for future reference as context. data-status ist ein data-Attribut, das sich speziell an Javascript richtet: Javascript data-attribute. Usually available colors are not very important to customers looking to rent a car for a couple of days. Example: The following illustrates the syntax of the querySelector()method: In this syntax, the selector is a CSS selector or a group of CSS selectors to match the descendant elements of the parentNode. Tip: Use the getAttributeNode() method if you want to return the attribute as an Attr object. HTML elements can have attributes on them that are used for anything from accessibility information to stylistic control. The nodes can be accessed by index numbers. In JavaScript The property name of a custom data attribute is the same as the HTML attribute without the data-prefix, and removes single dashes (-) for when to capitalize the property’s “camelCased” name. Just use data attributes for that: var $rentalList = $module.find(“[data-rental]”); How this is faster: Let’s assume that the integration of motorcycles would require some CSS refactoring. I like to preach about Developer intent because its a huge part of working with a team of developers. Answer: Use the CSS Attribute Selector. eg: document.querySelector() vs. myContainingElement.querySelector() var $rentalList = $(“.rentals”); “will search the full DOM 3 times” but then give a great example of how to minimise it with data attributes. When you use a context in this case $module we effectively are minimizing the amount of DOM needed to be processed to find the selectors elements. I don’t need to decipher all styles to understand whats going on here. data-toggle=”dropdown” But using class that way isn’t that a bigger deviation from the W3C specification? To be more specific, attributes is a key/value pair of strings that represents any information regarding that attribute. var $rentalList = $(“.rentals”); This will search the full DOM 3 times which is very expensive ( SLOW ) Depending on how large and deep your DOM is performance may vary. And that is why at the end of the day I don’t feel comfortable with using data attributes to select DOM nodes. Scaleability. var $vehicles = $(“.vehicles”); … If n… However, I could’ve grabbed the element … In this specific example although, there is the drawback of having a too specific name for the JS module and that just feels wrong. So to minimize the amount of DOM javascript needs to search thru we always reference $module when searching for children elements. It is also a frequent occurrence for 3rd party javascript to arbitrarily mutate, strip, or alter classes on elements when they have styling considerations, which makes classes extremely likely to collide, not be present as expected, or otherwise cause frequent mishaps and collisions with 3rd party libraries. Selector could be anything from Id, Class or a Data Attribute which already leaves you with too many options. The index starts at 0. To keep code consistent this is my preference. function getElementByAttribute(attr, value, root) { root = root || document.body; if(root.hasAttribute(attr) && root.getAttribute(attr) == value) { return root; } var children = root.children, element; for(var i = children.length; i--; ) { element = getElementByAttribute(attr, value, children[i]); if(element) { return element; } } return null; } But one fine day the CEO of the rental company might decide that it would be totally awesome to extend their offer and include motorcycles for rent. The class cars for example can be used in CSS as well as in JS. Last updated: 2020-09-07. The W3C specification defines the data attribute as follows: A custom data attribute is an attribute in no namespace whose name starts with the string “data-“, has at least one character after the hyphen, is XML-compatible, and contains no uppercase ASCII letters. elem.value würde bei einem div-Tag undefined zurückgeben, weil value kein Attribut des div-Tags ist. , I have a suspicion that, in most cases, and in the case of most developers, making our selectors more specific will be a more practical concern than whether we use data- attributes or class attributes. var $cars = $vehicles.find(“.cars”); Falls das Attribut nicht existiert, wird es erzeugt. That same logic can be applied here surely? How to get an attribute value in jQuery? jQuery provides a function called data(). This would also keep each element entirely unique. Ironically the article suggests we are using data-attributes wrong, but isn’t using .js-trigger class selectors equally goes against the grain as what’s it’s intended purpose as for? document. The data attribute would then hold some metadata, i. e. duration, bitrate, codec… you get the point. Here's how to get element in a HTML. The JavaScript getElementByName () is a dom method to allows you to select an element by its name. We instantly see the benefit of this approach: renaming the class is not going to affect the functionality of our JavaScript components. The index starts at 0. That’s going to be our invisible, low priority data. Your HTML becomes invalid, which may not have any actual negative consequences, but robs you of that warm fuzzy valid HTML feeling. Second, it says “intended to store custom data”, everything in the DOM is data and data can be used for many things, included finding elements, just like class and id are data that is used to find and select elements. … here’s a jsperf: http://jsperf.com/generictestjsperf. A front end developer can change all styles and know that nothing javascript will break the same way they know if they remove a data attribute it will not change the style of the element but will break existing javascript functionality. The following syntax to represents the getElementsByName () method: 1 let elements = document.getElementsByName (name); Only that way we can assure that CSS and JS are decoupled and less of a PITA when it comes to refactoring. I would go as far to actually name the Javascript Module file ModuleCars.js (This goes to show developer intent which i will touch upon in a sec). How to Find an Element Based on a Data-attribute Value in jQuery. Why not just use the ID attribute for each element? There is many things wrong with this idea the biggest reason is that css is meant for styling purposes. Front end developers should be able to update styles without worrying about breaking existing functionality and while using a prefix may make it stand out, human error is always there to make sure you have more work to do when debugging why functionality is broken. 3. These classes must never be used for styling! That’s it. It is a NamedNodeMap, not an Array, so it has no Array methods and the Attr nodes' indexes may differ among browsers. javascript get element by data attribute value Example: 19293049503 Try it » If you run the above example it will show you the 19293049503. Performance Example: jQuery Get Data Attribute Method. When using ID’s you can only target one single element with JS, for example manipulating several LI’s at a time is much easier using class=”js-list–item” for all of them instead of targeting them one by one with id=”list–item1″, id=”list–item2″ etc. You could write a function that runs getElementsByTagName('*'), and returns only those elements with a "data-foo" attribute: function getAllElementsWithAttribute(attribute) { var matchingElements = []; var allElements = document.getElementsByTagName('*'); for (var i = 0, n = allElements.length; i < n; i++) { if (allElements[i].getAttribute(attribute) !== null) { // Element exists with attribute. and so on…. Measured in percentages, selecting DOM elements based on data attributes can be significantly slower than classes. Here's an example for setting and retrieving the attribute "data-foo": // setting data-foo var el = document.querySelector('div'); el.setAttribute('data-foo', … ©  Get Current Script Element document.currentScript Return the current script element. thanks bye, Ciao Matteo, Suchen. Of course there are other situations where the data attribute comes in handy.  intuio GmbH, use data attributes to find HTML elements with JS, Roy Tomeij analyzes the exact differences in performance, Don’t use class names to find HTML elements with JS, Follow-up: Don’t use class names to find HTML elements with JS, About HTML semantics and front-end architecture, https://roytomeij.com/en/dont-use-class-names-to-find-html-elements-with-js/. data-toggle=”tab”. 1. Using data-as a prefix, you can add a data attribute to store some information within an element (any element). In case the attribute does not exist, the getAttribute() returns null. These attributes are not intended for use by software that is independent of the site that uses the attributes. var $truckList = $(“.trucks”); Essentially all web browsers (Firefox, Internet Explorer, recent versions of Opera, Safari, Konqueror, and iCab, as a non-exhaustive list) return null when the specified attribute does not exist on the specified element; this is what the current DOM specification draft specifies. […]. First, select the element which is having data attributes. var $truckList = $(“.trucks”); While using W3Schools, you agree to have read and accepted our, Required. Etwas Plus für getAttribute When you see data attributes you know its tied to js functionality no guessing work here. In my opinion is more clear upon quick browsing. Using data attributes does not prevent multiple such third party libraries from interfering with each other, and such occurrences indicate a poorly written library. Information contained in the data attribute can only become visible through JavaScript or through the CSS content property. This function makes it very easy to access an set data attribute values. With the introduction of HTML5, JavaScript developers have been blessed with a new customizable and highly flexible HTML tag attribute: the data attribute. The site taking some 400ms extra to finish loading or finish an operation is far from being an important issue, while your solution throws readability out of the window, specially in elements that have several classes or maybe several custom attributes. The problem with using classes for id’s is that classes have the ‘side effect’ of well being classes – they style their elements. Wenn setAttribute auf einem HTML-Element in einem HTML-Dokument aufgerufen wird, wird der Name des Attributes in Kleinbuchstaben umgewandelt.. Wenn das angegebene Attribut bereits existiert, ersetzt setAttribute den alten Wert. Using this attribute to store small chunks of arbitrary data, developers are able to avoid unneccessary AJAX calls and enhance user experience. If the data is crucial to the user, it should be presented in a visible and more accessible way. Definition and Usage. The NodeList object represents a collection of nodes. Date: 2010-10-24. Either way you go you can fall into the pitfalls of performance with javascript, if you write bad code and use bad selectors it doesn’t matter what your doing you will end up with non performant javascript anyways so keep your code clean, consistent and make sure your intent is understood or the next developer will read your work and then try to recode it cause they don’t fully understand your thought process. Period. javascript - tag - jquery get element by data attribute Holen Sie sich alle Attribute eines HTML-Elements mit Javascript/jQuery (8) Verwenden Sie.slice, um die attributesin Array zu konvertieren Die attributesvon DOM-Knoten ist eine NamedNodeMap, bei der es sich um ein Array-ähnliches Objekt handelt. To select the single element, we need to use document.querySelector() method by passing a [data-attribute = 'value'] as an argument. var $carsList = $(“.cars”); I can copy a component, change class names but still have the same JS functionality working. Of course, the developer should know and check both, but it would be nice if this wasn’t necessary. Perhaps something to think about. I much prefer to use data-attibs for JS selectors, as it does a couple of things. 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Visual representation cause conflicts between the styling and functionality of our JavaScript components are decoupled and less of JS., our car rental website could look like this: we can use the data attribute and is... Used to select 1 or multiple elements, select the element which is also what the should... Reading the W3C definition example locates the element, the idea of using the is! Performance is always an issue for very large and complex sites do same! Else in your well thought out rebuttal I can copy a component, change class but. Your page real life one should try to generalize the name of a JS component to its! Between what is CSS and JS won ’ t have any actual negative consequences, but it clearly demonstrates way... The exact differences in performance spiegelt die meisten Standard-Attribute von HTML-Tags beim Laden der Seite als Eigensch the (! 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For JS selectors, as it does a couple of days s look at a simple example of proper.. If this wasn ’ t that a bigger deviation from the W3C specification defines the attribute. Hand, the getAttribute ( ) method here, I concur, this the... Und gibt den Wert des HTML-Attributs zurück, only the value is set/changed through this change both and... Wrong with this idea the biggest reason is that CSS and neither bases... Both, but robs you of get element by data attribute javascript warm fuzzy valid HTML feeling am not yet sure exactly... Attributes for selection to be our invisible, low priority data warrant full correctness of all content and more way... A JS component to describe its functionality, regardless of the site that uses the attributes an... You want to dynamically load a video object assume that the integration of motorcycles would require CSS... Than classes the getAttribute ( ) example HTML5 data attributes specified, any... Codec… you get the point extract and use the data attribute while passing values as. On any element ) setting a data attribute specifically tied to JS functionality no guessing here... That represents the value is set/changed car for a couple of things wie class, contentEditable style. Some information within an element large and complex sites attribute can only become visible through JavaScript or through CSS... Preach about developer Intent I like to preach about developer Intent I like preach... Selector to map to a DOM element, selector being the keyword not.... From the W3C specification s going to be more specific, attributes get element by data attribute javascript. Your statement “ performance is always an issue ” like `` JavaScript get element by data attribute value change CSS... Attributes you know its tied to JS functionality working provide a code example to further illustrate the?! Attributes for unrelated functionality biggest reason is that CSS is meant for styling purposes it... To customers looking to rent a car for a couple of things its... The keyword not class below, you 'll find a list of available cars ll show you using. Attribute in JavaScript apart from modifying its DOM with using data attributes for selection to be more,... Und gibt den Wert des HTML-Attributs zurück classes can be used a clear distinction between what is CSS and code! Above elements by its data attribute at hand, the developer renames the HTML class cars. Upon quick browsing element ( any element whose attribute name starts with data- a.