get element by data attribute javascript

In Uncategorized by

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. 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. With the introduction of HTML5, JavaScript developers have been blessed with a new customizable and highly flexible HTML tag attribute: the data attribute. I think he is right. While using W3Schools, you agree to have read and accepted our, Required. Your HTML becomes invalid, which may not have any actual negative consequences, but robs you of that warm fuzzy valid HTML feeling. 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. Javascript spiegelt die meisten Standard-Attribute von HTML-Tags beim Laden der Seite als Eigensch First, select the element which is having data attributes. If the data is crucial to the user, it should be presented in a visible and more accessible way. data-toggle=”dropdown” The NodeList object represents a collection of nodes. The getElementsByClassName () method returns a collection of all elements in the document with the specified class name, as an HTMLCollection object. If the specified attribute already exists, only the value is set/changed. Through this change both CSS and JS won’t work anymore. With the new data attribute at hand, the idea of using the [data-foo='bar'] selector in JavaScript came along. To select the single element, we need to use document.querySelector() method by passing a [data-attribute = 'value'] as an argument. Approach 1: We can use the inbuilt setAttribute() function of JavaScript. You can use the CSS attribute selectors to find an HTML element based on its data-attribute value using jQuery. […]. Performance Example: 3. var list = $(“.cars”); The most extensible selector we can use would be the Data Attribute. Here you can see that two type of get data attribute methods are‘attribute’) method We can either use dataset property to get access to the data attributes or use .getAttribute() method to select them by specifically typing their names. The attribute selectors provide a very powerful way to select elements. How to append an element after an element using jQuery? The querySelector()allows you to find the first element, which is a descendant of the parent element on which it is invoked, that matches a CSS selector or a group of CSS selectors. The querySelector() is a method of the Element interface. Tip: Use the getAttributeNode() method if you want to return the attribute as an Attr object. document. An element's data-* attributes are retrieved the first time the data () method is invoked upon it, and then are no longer accessed or mutated (all values are stored internally by jQuery). The nodes can be accessed by index numbers. Perhaps something to think about. But using class that way isn’t that a bigger deviation from the W3C specification? The next example locates the element and reads the data attribute data-content2. The output will look something like this-Advertisements. Let’s look at a simple example of proper usage. 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 Element.attributes property returns a live collection of all attribute nodes registered to the specified node. Measured in percentages, selecting DOM elements based on data attributes can be significantly slower than classes. 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. Could you please provide a code example to further illustrate the problem? Custom data attributes are intended to store custom data private to the page or application, for which there are no more appropriate attributes or elements. Rotate the element based on an angle using CSS; How to append an element before an element using jQuery? Get code examples like "javascript get element by data attribute" instantly right from your google search results with the Grepper Chrome Extension. javascript get element by data attribute value Example: 19293049503 Try it » If you run the above example it will show you the 19293049503. The index starts at 0. Especially with complex systems where backend devs build the JS for callbacks etc. 1. 2. The name of the attribute you want to get the value from. 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. Scaleability. Every HTML element may have any number of custom data attributes specified, with any value. Prior to HTML5 we had to rely on using 'class' or 'rel' attributes to store little snippets of data that we could use in our websites. The getAttribute () method returns the value of the attribute with the specified name, of an element. Any attribute on any element whose attribute name starts with data- is a data attribute. The setAttribute () method adds the specified attribute to an element, and gives it the specified value. so even though there are performance issues, I still prefer data attributes to classes when designating id’s. Which is also what the libraries should have done to facilitate reuse, naturally. Thank you Chris Rivera, I concur, this is exactly what I was thinking reading this article. 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; } Information contained in the data attribute can only become visible through JavaScript or through the CSS content property. How to Find an Element Based on a Data-attribute Value in jQuery. Developer Intent To keep code consistent this is my preference. Transport. 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). According to him, this is only an issue for very large and complex sites. Etwas Plus für getAttribute Example: The nodes can be accessed by index numbers. Answer: Use the CSS Attribute Selector. This is the most expensive thing you can do in javascript apart from modifying its DOM. Finally, I highly disagree with your statement “performance is always an issue”. A String, representing the specified attribute's value. Every time you see $({*}), this will look thru the whole DOM to find the element you are looking for. 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. Javascript takes a selector to map to a DOM element, selector being the keyword not class. It is a NamedNodeMap, not an Array, so it has no Array methods and the Attr nodes' indexes may differ among browsers. 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. The HTMLCollection object represents a collection of nodes. 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. Example 1: This example uses dataset property to get the data attributes of an element. var $cars = $vehicles.find(“.cars”); 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. The use of data attributes shows the developer intent upon scanning as opposed to reading line by line: In my opinion is hard to read and complicated as more styling classes are used to generate the effective style. Hi, I was working with data- attribute and I was searching what is the best way of select html with this kind of selector. The following syntax to represents the getElementsByName () method: 1 let elements = document.getElementsByName (name); , 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. Integer oder Float) muss vom Javascript durchgeführt werden. Die Konvertierung in andere Datentypen (z.z. These attributes are not intended for use by software that is independent of the site that uses the attributes. The data attribute would then hold some metadata, i. e. duration, bitrate, codec… you get the point. 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. I agree with this. Usually available colors are not very important to customers looking to rent a car for a couple of days. 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. var $carsList = $(“.cars”); I can copy a component, change class names but still have the same JS functionality working. I dont think using the data attribute to find an element is a deviation from the w3c definition. The developer renames the HTML class from cars to vehicles. var $rentalList = $(“.rentals”); “will search the full DOM 3 times” but then give a great example of how to minimise it with data attributes. Date: 2010-10-24. So to minimize the amount of DOM javascript needs to search thru we always reference $module when searching for children elements. var $truckList = $(“.trucks”); The syntax is simple. I don’t need to decipher all styles to understand whats going on here. 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. eg: document.querySelector() vs. myContainingElement.querySelector() The getElementsByTagName() method returns a collection of an elements's child elements with the specified tag name, as a NodeList object. thanks bye, Ciao Matteo, 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. We instantly see the benefit of this approach: renaming the class is not going to affect the functionality of our JavaScript components. This would also keep each element entirely unique. All Javascript i write it tied to data-attributes, Now lets get down to performance. Using this attribute to store small chunks of arbitrary data, developers are able to avoid unneccessary AJAX calls and enhance user experience. We have also demostrate about the jquery set data attribute below. Tip: Use the getAttributeNode () method if you want to … I created a fund list and filtering tool. Why not just use the ID attribute for each element? Definition and Usage. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. The getElementById() method returns the element that has the ID attribute with the specified value. … There’s a clear distinction between what is JS and what is CSS and neither code bases pollute each other. 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). The problem with using classes for id’s is that classes have the ‘side effect’ of well being classes – they style their elements. 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. The trick is to rely on classes for DOM node selection in JavaScript to gain performance but to use a naming convention and strictly separate styling classes from logic classes. jQuery Get Data Attribute Method. If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail: var x = document.getElementsByTagName("H1")[0].getAttribute("class"); var x = document.getElementById("myAnchor").getAttribute("target"); var x = document.getElementById("myBtn").getAttribute("onclick"); W3Schools is optimized for learning and training. var $truckList = $module.find(“[data-truck]”); It always bugged me that dependencies between styling (CSS) and logic (JS) arise through shared classes. [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. The data attribute is meant to store small amounts of invisible data which is not crucial to the user and might become visible later on. This is the new link:, dom query selector performance is totally overrated, we have clients on 64bit 8g+ RAM, cuad-core 3ghz, they will be fine. What is discouraged is making upyour own attributes, or repurposing existing attributes for unrelated functionality. here’s a jsperf: data-Attribute sind Zeichenketten oder Strings, die alles speichern, was in einem String stehen kann – ähnlich wie JSON. Period. Thanks. HTML5 data attributes allow developers to add data to an element. Roy Tomeij adviced to use data attributes to find HTML elements with JS before and I have seen others do the same. Unlike setAttribute, the data() method will not physically change the data-list-size attribute — if you inspect its value outside of jQuery, it would still be ‘5’. That’s it. Definition and Usage. Now, how do you extract and use the data that are associated with the elements? Example:  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, In real life one should try to generalize the name of a JS component to describe its functionality, regardless of the content. Add Comment Read More. Data attribute while passing values such as config params is useful it can be used to select 1 or multiple elements. The advent of HTML5 introduced a new attribute known as 'data'. How to get an attribute value in jQuery? Applying this technique, our car rental website could look like this: We see the classes used in JavaScript are prefixed with js-. With the introduction of HTML5, JavaScript developers have been blessed with a new customizable and highly flexible HTML tag attribute: the data attribute. jQuery provides a function called data(). var $module = $(“[data-module=Cars]”); Just by looking at this code it would be easy to assume that data-module=Cars is related to javascript module called Cars. However, I could’ve grabbed the element … 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…. How to use jQuery hasAttribute() method to see if there is an attribute on an element? But then again, performance is always an issue and I don’t consider avoiding data attributes for selection to be premature optimization. As we can see, both CSS and JS use the same class to get their job done. classes are specifically used for styling and data attribute specifically tied to javascript functionality. The class cars for example can be used in CSS as well as in JS. Say you have an article and you want to store some extra information that doesn’t have any visual representation. These classes must never be used for styling! 1. The JavaScript getElementByName () is a dom method to allows you to select an element by its name. 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. I was just getting ready to disagree with you but after reading the W3C spec i think you may be right. And that is why at the end of the day I don’t feel comfortable with using data attributes to select DOM nodes. … Now, we need to select the above elements by data attribute in JavaScript. Returns null if not found. When you see data attributes you know its tied to js functionality no guessing work here. In addition to the information below, you'll find a how-to guide for using HTML data attributes in our article Using data attributes. This is all very basic stuff but it clearly demonstrates one way the data attribute can and should be used. You are not comfortable using data attributes, because it’s not written explicitly in the draft that you are allowed to use it that way. In his follow up article, Roy Tomeij analyzes the exact differences in performance. 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. Of course, the developer should know and check both, but it would be nice if this wasn’t necessary. data-status ist ein data-Attribut, das sich speziell an Javascript richtet: Javascript data-attribute. Say you want to dynamically load a video object. Here's an example for setting and retrieving the attribute "data-foo": // setting data-foo var el = document.querySelector('div'); el.setAttribute('data-foo', … The most compelling reason is that HTML is a living language and just because attributes and values that d… 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? What is it the best way of store the filter name and select it by js. HTML elements can have attributes on them that are used for anything from accessibility information to stylistic control. Roy’s article link was broken. Here's how to get element in a HTML. There are a variety of reasons this is bad. Get the value of the target attribute of an element: Get the value of the onclick event attribute of a