可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

I'm currently trying to make a cheap, simple slide show navigation box for a client (something along the lines of what, say, the Red Sox or Gamespot use on their sites, but far, far simpler). So far, it's actually coming along nicely, with one problem - the images don't appear upon a first visit. They only appear after the page is reloaded. I think it may be some sort of runtime issue, or perhaps a cache issue, but I'm not sure how to fix it. My code:

PHP:

if (isset($_GET['start']) && "true" === $_GET['start'])
{
    $images = array();

    if ($dir = dir('images'))
    {
        //$count = 0;

        while(false !== ($file = $dir->read()))
        {
            if (!is_dir($file) && $file !== '.' && $file !== '..' && (substr($file, -3) === 'jpg' || substr($file, -3) === 'png' || substr($file, -3) === 'gif'))
            {
                $lastModified = filemtime("{$dir->path}/$file");
                $images[$lastModified] = $file;
                //$images["image$count"] = $file;
                //++$count;
            }
        }

        echo json_encode($images);
    }
    else { echo "Could not open directory"; }
}

HTML and JavaScript:

<!doctype html>
<html lang="en-us">
    <head>
        <title>jQuery Cycle test</title>
        <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script>
        <script type="text/javascript" src="js/jquery.cycle.all.min.js"></script>
        <style>
            #slideshow a { margin: 0; padding: 0; color: #fff; }
        </style>
    </head>

    <body>
        <div id="slideshow">
        </div>
    </body>

    <script type="text/javascript">
        $.get('slideshow.php', {start : "true"}, function(data){
            var images = JSON.parse(data);

            for(var image in images){
                $('#slideshow').append('<a href="images/' + images[image] + '"><img src="images/' + images[image] + '" alt="" /></a>');
            }

            $('#slideshow').cycle({
                fx: 'cover',
                direction: 'right',
                timeout: 3000,
                speed: 300
            });
        });
    </script>

</html>

I think I may need to delay the timing of the cycle function, or perhaps somehow force it to 'see' the images the first time through. I'm just not sure how to do it.

回答1:

There are two possible reasons (or more that I am missing) that it could be loading oddly:

Your call isn't encompassed in a document.ready (even though your JavaScript code is at the bottom of the page) - this might not be the issue... just a thought.

i.e. create a function to hold your loading and do a:
```
$(document).ready(function(){
    loadImages();
    startSlideShow();
});
```
The other thing could be that on the first load, the images haven't downloaded to your browser. You could do a check to see if all the images have finished loading (use a counter and isloaded on all images etc.) before you show the cycle component. This could fix it for Chrome.

Note: The built-in .each is way way faster than a "for" loop. (specially for IE and many items...)

For example:

$(newImages).each(function(){
    $('#slideshow').append($(this));
});

回答2:

Since I wrote the original answer, I found that the same problem was occurring even with the timeout. I talked to the developer of the plugin on the jQuery forums, and his working example used $.getJSON rather than $.get. I switched to that, and it worked perfectly. I can only assume that there's some slight, subtle difference between how $.getJSON parses data and how I was doing it with the manual invocation of the parse function. Whether it's an actual code issue or timing issue of when the parsing is done remains a mystery.

My solution:

<!doctype html>
<html lang="en-us">
    <head>
        <title>jQuery Cycle test</title>
        <script type="text/javascript" src="js/jquery-1.4.2.min.js"></script>
        <script type="text/javascript" src="js/jquery.cycle.all.min.js"></script>

        <style>
            #slideshow a { margin: 0; padding: 0; color: #fff; display: block; }
            img { width: 305px; height: 278px; }
        </style>
    </head>

    <body>
        <div id="slideshow">
        </div>
    </body>

    <script type="text/javascript">     
        $.getJSON('slideshow.php', function(images){
            for(var i = 0; i < images.length; ++i){
                $('#slideshow').append('<a href="images/' + images[i]['src'] + '"><img src="images/' + images[i]['src'] + '" alt="" /></a>');
            }

            $('#slideshow').cycle({fx: 'cover', direction: 'right', timeout: 3000, speed: 300});
        });
    </script>

</html>

回答3:

Any idea how to get it to work with a regular get? This is what I am using:

    $.get(loadUrl, { id: id },
     function(data){
          $('#loader').remove();
             window.scrollTo(0,0);
          $('#display').html(data);             
          startCycle();
          });

function startCycle() {
     //trigger cycle
     $('.images').cycle({
          fx:     'fade',
          speed:  500,
          timeout: 0,
          pager: '#sub-nav .root',
          prev: "#sub-nav .prev",
          next: "#sub-nav .next",
          before: onAfter
      });

     $("#sub-nav a:first").addClass("first");
} //start cycle

The content that is being returned by ajax is a group of images as well as some text content.