Question

我有一个图像滑块。以下是滑块的屏幕截图。 enter image description here

这工作正常..它在点击下一个或上一个箭头时更改图像.. 但我想自动更改图像也意味着在某个时间间隔图像应该自动更改。我用谷歌搜索了很多，但我没有得到怎么做..请帮我解决这个问题...

提前致谢...

以下是代码：

<div id="slideshow">
        <ul class="slides">
            <li class="sl"><img class="ss" src="image/a.png" width="191" height="278" alt="Splash Screen" /></li>
            <li class="sl"><img class="ss" src="image/b.png" width="191" height="278" alt="Select Route" /></li>
            <li class="sl"><img class="ss" src="image/c.png" width="191" height="278" alt="New Schedule" /></li>
            <li class="sl"><img class="ss" src="image/d.png" width="191" height="278" alt="Created Routes" /></li>
            <li class="sl"><img class="ss" src="image/e.png" width="191" height="278" alt="CR" /></li>
        </ul>
        <span class="arrow next"></span>
        <span class="arrow previous"></span>
    </div>

以下是CSS：

#slideshow{
    background:url(res/iphone_small.png) no-repeat;
    height:512px;
    /*margin:auto 30px;*/
    margin:50px 25px auto;
    position:relative;
    width:257px;
}

#slideshow ul{
    height:300px;
    left:33px;
    list-style:none outside none;
    overflow:hidden;
    position:absolute;
    top:78px;
    width:257px;
}

#slideshow li{
    position:absolute;
    display:none;
    z-index:10;
}

#slideshow li:first-child{
    display:block;
    z-index:1000;
}

#slideshow .slideActive{
    z-index:1000;
}

#slideshow canvas{
    display:none;
    position:absolute;
    z-index:100;
}

#slideshow .arrow{
    height:64px;
    width:45px;
    position:absolute;
    background:url('res/arrows.png') no-repeat;
    top:50%;
    margin-top:-55px;
    cursor:pointer;
    z-index:5000;
    margin-left:240px;
    margin-right:240px;
}

#slideshow .previous{ background-position:right top;right:0;}
#slideshow .previous:hover{ background-position:right bottom;}

#slideshow .next{ background-position:left top;left:0;}
#slideshow .next:hover{ background-position:left bottom;}

以下是js文件：

$(window).load(function(){

    // We are listening to the window.load event, so we can be sure
    // that the images in the slideshow are loaded properly.


    // Testing wether the current browser supports the canvas element:
    var supportCanvas = 'getContext' in document.createElement('canvas');

    // The canvas manipulations of the images are CPU intensive,
    // this is why we are using setTimeout to make them asynchronous
    // and improve the responsiveness of the page.

    var slides = $('#slideshow li'),
        current = 0,
        slideshow = {width:0,height:0};

    setTimeout(function(){

        window.console && window.console.time && console.time('Generated In');

        if(supportCanvas){
            $('#slideshow img').each(function(){

                if(!slideshow.width){
                    // Taking the dimensions of the first image:
                    slideshow.width = this.width;
                    slideshow.height = this.height;
                }

                // Rendering the modified versions of the images:
                createCanvasOverlay(this);
            });
        }

        window.console && window.console.timeEnd && console.timeEnd('Generated In');

        $('#slideshow .arrow').click(function(){
            var li          = slides.eq(current),
                canvas      = li.find('canvas'),
                nextIndex   = 0;

            // Depending on whether this is the next or previous
            // arrow, calculate the index of the next slide accordingly.

            if($(this).hasClass('next')){
                nextIndex = current >= slides.length-1 ? 0 : current+1;
            }
            else {
                nextIndex = current <= 0 ? slides.length-1 : current-1;
            }

            var next = slides.eq(nextIndex);

            /*if(supportCanvas){

                // This browser supports canvas, fade it into view:

                canvas.fadeIn(function(){

                    // Show the next slide below the current one:
                    next.show();
                    current = nextIndex;

                    // Fade the current slide out of view:
                    li.fadeOut(function(){
                        li.removeClass('slideActive');
                        canvas.hide();
                        next.addClass('slideActive');
                    });
                });
            }
            else {*/

                // This browser does not support canvas.
                // Use the plain version of the slideshow.

                current=nextIndex;
                next.addClass('slideActive').show();
                li.removeClass('slideActive').hide();
            //}
        });

    },100);

    // This function takes an image and renders
    // a version of it similar to the Overlay blending
    // mode in Photoshop.

    function createCanvasOverlay(image){

        var canvas          = document.createElement('canvas'),
            canvasContext   = canvas.getContext("2d");

        // Make it the same size as the image
        canvas.width = slideshow.width;
        canvas.height = slideshow.height;

        // Drawing the default version of the image on the canvas:
        canvasContext.drawImage(image,0,0);


        // Taking the image data and storing it in the imageData array:
        var imageData   = canvasContext.getImageData(0,0,canvas.width,canvas.height),
            data        = imageData.data;

        // Loop through all the pixels in the imageData array, and modify
        // the red, green, and blue color values.

        for(var i = 0,z=data.length;i<z;i++){

            // The values for red, green and blue are consecutive elements
            // in the imageData array. We modify the three of them at once:

            data[i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));
            data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));
            data[++i] = ((data[i] < 128) ? (2*data[i]*data[i] / 255) : (255 - 2 * (255 - data[i]) * (255 - data[i]) / 255));

            // After the RGB elements is the alpha value, but we leave it the same.
            ++i;
        }

        // Putting the modified imageData back to the canvas.
        canvasContext.putImageData(imageData,0,0);

        // Inserting the canvas in the DOM, before the image:
        image.parentNode.insertBefore(canvas,image);
    }

});

Answer 1

又快又脏：

var $nextButton = $('#slideshow .next');
var interval = 2000; // we go to next pic every 2 seconds

setInterval(function(){

    // we trigger nextImage event manually
    $nextButton.click();

}, interval);

Answer 2

  setInterval(function(){
       $('#slideshow .next').click();
  },1000);

Answer 3

点击此链接：https://www.w3schools.com/howto/howto_js_slideshow.asp

它展示了如何同时创建自动幻灯片和手动幻灯片。

这是自动的

var slideIndex = 0;
carousel();

function carousel() {
    var i;
    var x = document.getElementsByClassName("mySlides");
    for (i = 0; i < x.length; i++) {
      x[i].style.display = "none"; 
    }
    slideIndex++;enter code here
    if (slideIndex > x.length) {slideIndex = 1} 
    x[slideIndex-1].style.display = "block"; 
    setTimeout(carousel, 2000); // Change image every 2 seconds
}

如何制作自动图像滑块。

3 个答案: