Question

我有以下javascript

function fadeIn(objectID, amount) {
object = document.getElementById(objectID + 'Des');
if(amount > 0)
{
    object.style.display ='block';
    object.style.opacity = '0';
}
var i = 0;
animatefadein = function()
{
    var MIN_OPACITY = 0;
    var MAX_OPACITY = 1;
    if ( (amount > 0 && object.style.opacity < MAX_OPACITY) || (amount < 0 && object.style.opacity > MIN_OPACITY)) 
    {
        var current = Number(object.style.opacity);
        var newopac = current + Number(amount);
        object.style.opacity = String(newopac);
        setTimeout('animatefadein()', 50);

    }

}
animatefadein();
if(amount < 0)
{
    object.style.display ='none';
}

}

我需要将display设置为none，因为如果用户浏览它们，则需要放置另一个元素。

这是HTML，

<div id='products'>
            <img src = './product1.png' usemap='#ourProducts' alt='Our Products' title='Hover over the names to find out more.'>
            <map id='ourProducts' name='ourProducts'>
                <area shape='rect' coords="55,55,210,110" href='#' id='forcePort' alt='ForcePort' title='ForcePort' onmouseover='fadeIn("forcePort",0.1)' onmouseout='fadeIn("forcePort",-0.1)'/>
                <area shape='rect' coords="105,248,270,290" href='#' id='quickPort' alt='QuickPort' title='QuickPort' onmouseover='fadeIn("quickPort",0.1)' onmouseout='fadeIn("quickPort",-0.1)'/>
                <area shape='rect' coords="390,260,535,303" href='#' id='scrinter' alt='Scrinter' title='Scrinter' onmouseover='fadeIn("scrinter",0.1)' onmouseout='fadeIn("scrinter",-0.1)'/>
                <area shape='rect' coords="675,242,835,292" href='#'  id='bugTrail' alt='Bug Trail' title='Bug Trail' onmouseover='fadeIn("bugTrail",0.1)' onmouseout='fadeIn("bugTrail",-0.1)'/>
                <area shape='rect' coords="688,42,858,138" href='#' id='dataExtract' alt='CRM Data Extractor' title='CRM Data Extractor' onmouseover='fadeIn("dataExtract",0.1)' onmouseout='fadeIn("dataExtract",-0.1)'/>
            </map>
            <div id='productDes'>
                <div id='scrinterDes'>
                                      Data that needs to be shown!
                </div>
                <div id='bugTrailDes'>
                </div>
                <div id='quickPortDes'>
                </div>
                <div id='forcePortDes'>
                </div>
                <div id='dataExtractDes'>
                </div>
            </div>
        </div>

正如您所看到的淡出效果无效。此外，如果您在setTimeout循环中放置一个计数器并将其打印到控制台，您将看到它在淡出事件中循环不计数次。这是相关网站，

Website

只需转到显示屏上的产品，然后将鼠标悬停在产品名称上即可。

Answer 1

我希望您意识到使用jQuery很容易实现这一点http://jquery.com/您的脚本存在的问题是Opacity和Display是两个不同的CSS属性，以使其工作，您需要将Opacity设置为0，将Display: none更改为block或inline-block，然后为Opacity

设置动画

Answer 2

请在此处查看：http://jsfiddle.net/V8SAx/

首先，您不应该像setTimeout那样致电setTimeout('animatefadein()', 50)，因为它使用eval，这是非常缓慢且不安全的。

其次，这里有代码：

function fadeIn(objectID, amount,callback) {
    object = document.getElementById(objectID + 'Des');
    object.style.display ='block';
    object.style.opacity = String(Number(amount<0));
    animatefadein = function()
    {
        var MIN_OPACITY = 0;
        var MAX_OPACITY = 1;
        if ( (amount > 0 && object.style.opacity < MAX_OPACITY) ||
             (amount < 0 && object.style.opacity > MIN_OPACITY)
        ){
            var current = Number(object.style.opacity);
            var newopac = current + Number(amount);
            console.log(current + Number(amount));
            object.style.opacity = String(newopac);
            setTimeout(animatefadein, 50);

        }else{
            if(amount<0){object.style.display='none';}
            if(callback){callback();}
        }

    }
    animatefadein();
}
fadeIn('a',0.1,function(){fadeIn('a',-0.1);});

我已经添加了对回调的支持，这个回调在淡入淡出过程之后被调用，也许它让你感兴趣。

元素渐渐消失，但不会淡出

2 个答案: