Element matches / matchesSelector

By  on  

I was thinking about HTML elements and selectors recently.  We usually start by searching for an element(s) via querySelector/querySelectorAll, which makes sense, but what if you want to validate that an element that wasn't specifically selected matches a given selector?  For example, say you have a function which assumes the presence of classes or attributes on the elements it has been passed, and things might go wrong if the element provided doesn't fit the bill?  Enter Element.matches!

The JavaScript

As MDN details, Element.matches is the standard API but each vendor has implemented a matchesSelector version:

function determineIfElementMatches(element, selector) {
	return element.matches(selector);
}

// Sample usage
var matches = determineIfElementMatches(myDiv, 'div.someSelector[some-attribute=true]');

To work around all of the vendor mess, we can just use the Element prototype:

function selectorMatches(el, selector) {
	var p = Element.prototype;
	var f = p.matches || p.webkitMatchesSelector || p.mozMatchesSelector || p.msMatchesSelector || function(s) {
		return [].indexOf.call(document.querySelectorAll(s), this) !== -1;
	};
	return f.call(el, selector);
}

I've included a polyfill if the browser doesn't support matches but modern browsers should support the function in some form. As I mentioned at the beginning of the post, I think `matches` is probably most used as a validation measure, but let me know if you see better uses!

Recent Features

  • By
    Interview with a Pornhub Web Developer

    Regardless of your stance on pornography, it would be impossible to deny the massive impact the adult website industry has had on pushing the web forward. From pushing the browser's video limits to pushing ads through WebSocket so ad blockers don't detect them, you have...

  • By
    Creating Scrolling Parallax Effects with CSS

    Introduction For quite a long time now websites with the so called "parallax" effect have been really popular. In case you have not heard of this effect, it basically includes different layers of images that are moving in different directions or with different speed. This leads to a...

Incredible Demos

  • By
    Creating the Treehouse Frog Animation

    Before we start, I want to say thank you to David for giving me this awesome opportunity to share this experience with you guys and say that I'm really flattered. I think that CSS animations are really great. When I first learned how CSS...

  • By
    jQuery Countdown Plugin

    You've probably been to sites like RapidShare and MegaUpload that allow you to download files but make you wait a specified number of seconds before giving you the download link. I've created a similar script but my script allows you to animate the CSS font-size...

Discussion

  1. MaxArt

    The polyfill isn’t very useful, as it should be targeted to IE8 only (IE9 supports msMatchesSelector), but IE8 doesn’t support indexOf in arrays – unless you’re again using a polyfill, of course.

    This also mean that, potentially, the polyfill is much slower. Even slower if you’re planning to polyfill for IE7-, as it doesn’t even support querySelectorAll.

  2. Felipe

    Element.matches can it get another attributes like src or rel?

  3. I added this in our compatibility js library we use at work.
    This way we can write for modern browsers without mixing fallback code into site specific code.
    When the time comes we can easily remove obsolete fallbacks like these from our library, do a republish on our sites and all the obsolete fallback code is gone.

    if (!Element.prototype.matches)
    {
      var ep = Element.prototype;
    
      if (ep.webkitMatchesSelector) // Chrome <34, SF<7.1, iOS<8
        ep.matches = ep.webkitMatchesSelector;
    
      if (ep.msMatchesSelector) // IE9/10/11 & Edge
        ep.matches = ep.msMatchesSelector;
    
      if (ep.mozMatchesSelector) // FF<34
        ep.matches = ep.mozMatchesSelector;
    }
    
  4. no

    this doesn’t work if you are testing an element that has been removed from the document or is in a document fragment.

  5. Amir Saleem

    We can use hasClass() and hasId() methods to determine if the clicked element has a given class or id.

      
      function hasClass(elem, match){
           return elem.className.split(" ").indexOf(match) > -1 ;
       }
    
      function hasId(elem, match){
           return elem.id.split(" ").indexOf(match) > -1 ;
       }
    
    

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!