javascript - 当从子元素调用的 javascript 更改类时，CSS 转换不起作用

Question

我创建了一个模态窗口，它会在您单击 anchor 时淡入淡出。这个的 HTML 非常简单:

<div id="main_wrapper" class="displayed">
    //Some content here
</div>
<div id="dynamic">
    //Dynamically generated (AJAX) content here
    //the below anchor skips the CSS transition somehow!
    <a href='#' onclick='toggleDynamic(); return false;'>Cancel</a>
</div>

//This anchor works exactly as intended
<a href='#' onclick='toggleDynamic(); return false;'>Dynamic</a>

CSS 稍微复杂一些，为了简洁起见，我省略了一些属性:

.displayed{
    opacity:        1 !important;
    pointer-events: auto !important;
    transition:     opacity 1s ease-in .5s !important;
}

#main_wrapper{
    max-width:      800px;
    opacity:        0;
    pointer-events: none;
    transition:     opacity 1s linear;
}

#dynamic{
    position:       fixed;
    display:        block;
    opacity:        0;
    pointer-events: none;
    max-width:      800px;
    transition:     opacity 1s linear;
}

然后我简单地使用一个切换 javascript 函数:

function $I(id) {
    return document.getElementById(id);
}

var dynamic = $I('dynamic');
var main = $I('main_wrapper');

function toggleDynamic() {
    if(dynamic.className === "") {
        dynamic.className = "displayed";
        main.className = "";
    } else {
        dynamic.className = "";
        main.className = "displayed";
    }
}

除了一件事，上面的所有代码都完全按预期工作 - 当点击#dynamic 中的 anchor 时，div 会消失而没有过渡!我无法理解这一点，因为您可以整天单击外部 anchor 并获得漂亮的淡入淡出过渡。

据我所知，这发生在所有浏览器中(IE、FF、Chrome、Opera)。

编辑:我已经更改了 javascript，因为它之前没有正确处理类名。

Answer 1

我不明白为什么你的 JS 会像现在这样工作，因为你没有修改你的 #dynamic 类，而只是一个变量 (dynamic)。对我来说，更正后的片段就像​​一个魅力。

function $I(id) {
    return document.getElementById(id);
}

var dynamic = $I('dynamic').className;
var main = $I('main_wrapper').className;

function toggleDynamic() {
    if($I('dynamic').className === "") {
        $I('dynamic').className = "displayed";
        main = "";
    } else {
        $I('dynamic').className = "";
        main = "displayed";
    }
}

.displayed{
  opacity:        1 !important;
  pointer-events: auto !important;
  transition:     opacity 1s ease-in .5s !important;
}

#main_wrapper{
  max-width:      800px;
  opacity:        0;
  pointer-events: none;
  transition:     opacity 1s linear;
}

#dynamic{
  position:       fixed;
  display:        block;
  opacity:        0;
  pointer-events: none;
  max-width:      800px;
  transition:     opacity 1s linear;
}

<div id="main_wrapper" class="displayed">
    //Some content here
</div>
<div id="dynamic">
    //Dynamically generated (AJAX) content here
    //the below anchor skips the CSS transition somehow!
    <a href='#' onclick='toggleDynamic(); return false;'>Cancel</a>
</div>
//This anchor works exactly as intended
<a href='#' onclick='toggleDynamic(); return false;'>Dynamic</a>