javascript - setTimeout 似乎没有调用该函数

Question

在我添加 setTimeout 之前，代码运行得很好。现在，无论我如何尝试调用 setTimeout 中的函数 ( setTimeout(function(){fadeOut()},1000); setTimeout("fadeOut()",1000); 等)似乎根本没有达到该功能。

我是 Javascript 新手，因此非常感谢您的帮助 =]

JavaScript 代码:

var slideArray = ["slide1","slide2","slide3","slide4","slide5","slide6"];
var currentSlide = null;
var current = null;
var done = false;

function fade(newSlide)
{
    if(currentSlide === null)
    {
        currentSlide = slideArray[0];
        document.getElementById(currentSlide).style.opacity = 1.0;

        for(var i=1;i<slideArray.length;i++)
            document.getElementById(slideArray[i]).style.opacity = 0.0;
    }

    current = document.getElementById(currentSlide);
    done = false;
    do
    {
        window.setTimeout(fadeOut,1000);
    } while(done == false);

    currentSlide = newSlide;
    current = document.getElementById(currentSlide);
    done = false;

    do
    {
        window.setTimeout(fadeIn,1000);
    } while(done == false);
}

function fadeOut()
{
    if(parseFloat(current.style.opacity)-0.1>.0000001)
    {
    current.style.opacity = parseFloat(current.style.opacity) -0.1;
        done = false;
    }
    else
    {
        current.style.opacity = 0.0;
        done = true;
    }
}

function fadeIn()
{
    if(0.9-parseFloat(current.style.opacity)>.0000001)
    {
        current.style.opacity = parseFloat(current.style.opacity)+0.1;
        done = false;
    }
    else
    {
        current.style.opacity = 1.0;
        done = true;
    }
}

Answer 1

您不能使用此结构:

do
{
    window.setTimeout(fadeIn,1000);
} while(done == false);

因为 setTimeout() 中的代码稍后运行，所以您的 did 值永远不会改变，并且这个循环将永远运行。而且，只要它运行，setTimeout() 也永远不会触发(因为 javascript 是单线程的)。

相反，如果还没有完成，您应该做的是从 fadeIn() 函数启动下一个 setTimeout(fadeIn, 1000)。

function fadeOut()
{
    if(parseFloat(current.style.opacity)-0.1>.0000001)
    {
        current.style.opacity = parseFloat(current.style.opacity) -0.1;
        setTimeout(fadeOut, 1000);
    }

    else
    {
        current.style.opacity = 0.0;
    }
}