How do I simulate a hover with a touch in touch enabled browsers?

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旧巷少年郎
旧巷少年郎 2020-11-22 17:04

With some HTML like this:

Some Text

Then some CSS like this:

p {
  color:black;
}

p:hover {
  color:red         


        
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14条回答
  • 2020-11-22 17:16

    To answer your main question: “How do I simulate a hover with a touch in touch enabled browsers?”

    Simply allow ‘clicking’ the element (by tapping the screen), and then trigger the hover event using JavaScript.

    var p = document.getElementsByTagName('p')[0];
    p.onclick = function() {
     // Trigger the `hover` event on the paragraph
     p.onhover.call(p);
    };
    

    This should work, as long as there’s a hover event on your device (even though it normally isn’t used).

    Update: I just tested this technique on my iPhone and it seems to work fine. Try it out here: http://jsfiddle.net/mathias/YS7ft/show/light/

    If you want to use a ‘long touch’ to trigger hover instead, you can use the above code snippet as a starting point and have fun with timers and stuff ;)

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  • 2020-11-22 17:18

    My personal taste is to attribute the :hover styles to the :focus state as well, like:

    p {
        color: red;
    }
    
    p:hover, p:focus {
        color: blue;
    }
    

    Then with the following HTML:

    <p id="some-p-tag" tabindex="-1">WOOOO</p>
    

    And the following JavaScript:

    $("#some-p-tag").on("touchstart", function(e){
        e.preventDefault();
        var $elem = $(this);
    
        if($elem.is(":focus")) {
            //this can be registered as a "click" on a mobile device, as it's a double tap
            $elem.blur()
        }
        else {
            $elem.focus();
        }
    });
    
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  • 2020-11-22 17:23

    OK, I've worked it out! It involves changing the CSS slightly and adding some JS.

    Using jQuery to make it easy:

    $(document).ready(function() {
        $('.hover').on('touchstart touchend', function(e) {
            e.preventDefault();
            $(this).toggleClass('hover_effect');
        });
    });
    

    In english: when you start or end a touch, turn the class hover_effect on or off.

    Then, in your HTML, add a class hover to anything you want this to work with. In your CSS, replace any instance of:

    element:hover {
        rule:properties;
    }
    

    with

    element:hover, element.hover_effect {
        rule:properties;
    }
    

    And just for added usefulness, add this to your CSS as well:

    .hover {
    -webkit-user-select: none;
    -webkit-touch-callout: none;        
    }
    

    To stop the browser asking you to copy/save/select the image or whatever.

    Easy!

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  • 2020-11-22 17:23

    Further Improved Solution

    First I went with the Rich Bradshaw's approach, but then problems started to appear. By doing the e.preventDefault() on 'touchstart' event, the page no longer scrolls and, neither the long press is able to fire the options menu nor double click zoom is able to finish executing.

    A solution could be finding out which event is being called and just e.preventDefault() in the later one, 'touchend'. Since scroll's 'touchmove' comes before 'touchend' it stays as by default, and 'click' is also prevented since it comes afterwords in the event chain applied to mobile, like so:

    // Binding to the '.static_parent' ensuring dynamic ajaxified content
    $('.static_parent').on('touchstart touchend', '.link', function (e) {
    
        // If event is 'touchend' then...
        if (e.type == 'touchend') {
            // Ensuring we event prevent default in all major browsers
            e.preventDefault ? e.preventDefault() : e.returnValue = false;
        }
    
        // Add class responsible for :hover effect
        $(this).toggleClass('hover_effect');
    });
    

    But then, when options menu appears, it no longer fires 'touchend' responsible for toggling off the class, and next time the hover behavior will be the other way around, totally mixed up.

    A solution then would be, again, conditionally finding out which event we're in, or just doing separate ones, and use addClass() and removeClass() respectively on 'touchstart' and 'touchend', ensuring it always starts and ends by respectively adding and removing instead of conditionally deciding on it. To finish we will also bind the removing callback to the 'focusout' event type, staying responsible for clearing any link's hover class that might stay on and never revisited again, like so:

    $('.static_parent').on('touchstart', '.link', function (e) {
        $(this).addClass('hover_effect');
    });
    
    $('.static_parent').on('touchend focusout', '.link', function (e) {
        // Think double click zoom still fails here
        e.preventDefault ? e.preventDefault() : e.returnValue = false;
        $(this).removeClass('hover_effect');
    });
    

    Atention: Some bugs still occur in the two previous solutions and, also think (not tested), double click zoom still fails too.

    Tidy and Hopefully Bug Free (not :)) Javascript Solution

    Now, for a second, cleaner, tidier and responsive, approach just using javascript (no mix between .hover class and pseudo :hover) and from where you could call directly your ajax behavior on the universal (mobile and desktop) 'click' event, I've found a pretty well answered question from which I finally understood how I could mix touch and mouse events together without several event callbacks inevitably changing each other's ones up the event chain. Here's how:

    $('.static_parent').on('touchstart mouseenter', '.link', function (e) {
        $(this).addClass('hover_effect');
    });
    
    $('.static_parent').on('mouseleave touchmove click', '.link', function (e) {
        $(this).removeClass('hover_effect');
    
        // As it's the chain's last event we only prevent it from making HTTP request
        if (e.type == 'click') {
            e.preventDefault ? e.preventDefault() : e.returnValue = false;
    
            // Ajax behavior here!
        }
    });
    
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  • 2020-11-22 17:23

    One way to do it would be to do the hover effect when the touch starts, then remove the hover effect when the touch moves or ends.

    This is what Apple has to say about touch handling in general, since you mention iPhone.

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  • 2020-11-22 17:25

    All you need to do is bind touchstart on a parent. Something like this will work:

    $('body').on('touchstart', function() {});
    

    You don't need to do anything in the function, leave it empty. This will be enough to get hovers on touch, so a touch behaves more like :hover and less like :active. iOS magic.

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