Since the question refers to a single element, this code might be more suitable: It is the same as twernt’s suggestion, but applied to a single element; and it matches the algorithm recommended in the jQuery FAQ. We use jQuery’s is() to check the selected element with another element, selector or any jQuery object. This method traverses along the … Read more
You can use .length with just a descendant selector, like this: If you have to use .children(), then it’s like this: You can test both versions here.
In response to the original question, you are using for/in incorrectly. In your code, key is the index. So, to get the value from the pseudo-array, you’d have to do list[key] and to get the id, you’d do list[key].id. But, you should not be doing this with for/in in the first place. Summary (added in … Read more
Modern HTML5 Techniques for changing classes Modern browsers have added classList which provides methods to make it easier to manipulate classes without needing a library: Unfortunately, these do not work in Internet Explorer prior to v10, though there is a shim to add support for it to IE8 and IE9, available from this page. It is, though, getting more and … Read more
A “node”, in this context, is simply an HTML element. The “DOM” is a tree structure that represents the HTML of the website, and every HTML element is a “node”. See Document Object Model (DOM). More specifically, “Node” is an interface that is implemented by multiple other objects, including “document” and “element”. All objects implementing the “Node” interface … Read more
Create a dummy DOM element and add the string to it. Then, you can manipulate it like any DOM element. Edit: adding a jQuery answer to please the fans!
Use element.classList .contains method: This works on all current browsers and there are polyfills to support older browsers too. Alternatively, if you work with older browsers and don’t want to use polyfills to fix them, using indexOf is correct, but you have to tweak it a little: Otherwise you will also get true if the class you are looking for is part … Read more
Here’s more information on MDN: className
You can use the jQuery attribute selector:
It seems some people are landing here, and simply want to know if an element exists (a little bit different to the original question). That’s as simple as using any of the browser’s selecting method, and checking it for a truthy value (generally). For example, if my element had an id of “find-me”, I could … Read more