Javascript jquery淡入/淡出循环，如何使用计时器？ [英] Javascript jquery fade-in/fadeout loop, how to use timer?

问题描述

javascript等新手，尝试使用jquery创建一个用于淡化徽标的循环。

New to javascript and such, trying to create a loop for fading logos using jquery.

我已经让它循环通过它们就好了。但我试图使循环连续;这样，当它到达最后一个标识时，它会回到开头，每次到达最后一个标识时，将我的柜台重置为0。这导致了无限循环，我认为这会使我的浏览器崩溃。所以我做了一个快速谷歌并发现了window.setInterval（...）计时器功能。

I've got it cycling through them just fine. But i tried to make the loop continuous; so that when it reached the last logo it went back to the beginning, by resetting my for-counter to 0 every time it reached the last logo. This resulted in an infinite loop i think that crashed my browser. So i did a quick google and discovered the window.setInterval(...) timer function.

我的问题是，现在解雇循环代码依赖于时间，我无法弄清楚如何计算间隔时间。 For这里引用的是用于淡入和退出徽标的代码（在尝试循环之前）：

My problem is, now that firing the looping code relies on timing, i can't figure out how to calculate the interval time. For reference here's the code that fades the logos in and out (before trying to loop it):

$(document).ready(function (){

    var fadeDuration = 1000;
    var timeBetweenFade = 2000;
    var totalTimePerChange = fadeDuration + timeBetweenFade;
    var totalLogos = $('.logo').length;
    var currentLogo;
    var i;

        for(i = 0; i < totalLogos; i++)
        {
            currentLogo = "#img" + i;
            if(i == 0){
                $(currentLogo).fadeIn(fadeDuration).delay(timeBetweenFade).fadeOut(fadeDuration);
                }
            else{ //general case
                $(currentLogo).delay(totalTimePerChange * i).fadeIn(fadeDuration).delay(timeBetweenFade).fadeOut(fadeDuration);
            }
        }
});

我试图通过几种方式获得完整循环的时间：

I tried to get the time a complete loop took in a couple of ways:

$(document).ready(function (){

    //..declarations..

    window.setInterval( function() {
        //..FOR LOOP HERE..
    }, i*(fadeDuration + timeBetweenFade + fadeDuration));
});

//I also tried..

$(document).ready(function (){

    //..declarations..
    var timeTakenToLoop;
    var startLoopTime;

    window.setInterval( function() {
    startLoopTime = new Date().getTime();
        //...FOR LOOP HERE..
    timeTakenToLoop = new Date().getTime() - startLoopTime;
    }, timeTakenToLoop);
});

但在这两种情况下，由于函数调用时序错误，我得到的徽标开始重叠。有经验的人可以建议最好的方法吗？

哦，以防万一有人需要它来理解javascript，这里是html匹配..

Oh and just in case anyone needs it to understand the javascript, here's the html to match..

    <div id="img0" class="logo">
    <img src="{% static "CSS/Images/phone_icon.gif" %}"/>
    </div>
    <div id="img1" class="logo">
    <img src="{% static "CSS/Images/email_icon.gif" %}"/>
    </div>
    <div id="img2" class="logo">I can fade too</div>

推荐答案

简单的jQuery方法，没有 setTimeout 并且没有 setInterval 。

Simple jQuery approach, no setTimeout and no setInterval.

var loop = function(idx, totalLogos) {
  var currentLogo = "#img" + idx;
  $(currentLogo)
    .delay(currentLogo)
    .fadeIn(fadeDuration)
    .delay(currentLogo)
    .fadeOut(fadeDuration, function(){
      loop( (idx + 1) % totalLogos, totalLogos);
    });
}
loop(0, $('.logo').length);​

在此处查看。

这篇关于Javascript jquery淡入/淡出循环，如何使用计时器？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！