How can I feature-detect CSS filters?

问题:

In some browsers, including Chrome stable, you can do this:

h3 {
  -webkit-filter: grayscale(1);
  filter: grayscale(1);
}

And wouldn’t you know it, the h1 will be rendered completely in grayscale. Everything old is new again.

Anyway — does anyone know of any way to feature-detect for this?

I need to be able to apply other styles if fil filter won’t work.

回答1:

So called UPDATED answer:

As the OP mentioned a good point I'm updating the answer but this does not have anything related or in contradict with my previous answer, this is simply a browser detection.

Alan H. mentioned that IE, prior to its 10th. version, supports filter css property but not in the way we all know about it (CSS3 filter I meant).

So If we want to feature detect CSS3 filters only, we should go ahead and use a little browser-detection. As I mentioned in my comments.

Using documentMode property, and combining it with our simple feature-detect we can exclude so called false positives in IE.

function css3FilterFeatureDetect(enableWebkit) {
    //As I mentioned in my comments, the only render engine which truly supports
    //CSS3 filter is webkit. so here we fill webkit detection arg with its default
    if(enableWebkit === undefined) {
        enableWebkit = false;
    }
    //creating an element dynamically
    el = document.createElement('div');
    //adding filter-blur property to it
    el.style.cssText = (enableWebkit?'-webkit-':'') + 'filter: blur(2px)';
    //checking whether the style is computed or ignored
    //And this is not because I don't understand the !! operator
    //This is because !! is so obscure for learning purposes! :D
    test1 = (el.style.length != 0);
    //checking for false positives of IE
    //I prefer Modernizr's smart method of browser detection
    test2 = (
        document.documentMode === undefined //non-IE browsers, including ancient IEs
        || document.documentMode > 9 //IE compatibility moe
    );
    //combining test results
    return test1 && test2;
}

Original Modernizr source

---

if(document.body.style.webkitFilter !== undefined)

or

if(document.body.style.filter !== undefined)

Extra information:

For just a simple feature detection use my codes above. For a list of supported functions, take a look at here:

• Filter Effects 1.0
• Filter Effects 1.0 functions

For a live demonstration of filters in Chrome, take a look at here:

• CSS Filter Effects

And 2 more resources for you:

• CSS Filter Effects Landing in WebKit
• When can I use CSS Filter Effects?

As I'm writing this answer, you must use webkit vendor prefix to make it to work.