Question

我试图将div转换为宽度（放大），但我希望它从中心而不是左上角增长

HTML

<div id="attach-wrap">
        <div id="attach">

            ... content ...

        </div>
    </div>

CSS ＃attach-wrap {min-height：50px; }

#attach { 
  height: 50px;
  width: 60%;
  margin: 0 auto;
  border-top: 1px solid #000;
  border-bottom: 1px solid #000;
  -webkit-transition: height 0.35s ease, width 0.35s ease;
  -moz-transition: height 0.35s ease, width 0.35s ease;
  -ms-transition: height 0.35s ease, width 0.35s ease;
  -o-transition: height 0.35s ease, width 0.35s ease;
  transition: height 0.35s ease, width 0.35s ease; 
}

#attach.stick { 
  height: 80px; 
  width: 100%;
  border-bottom: 1px solid #000;
  background-color: rgba(250,250,250,1);
  position: fixed;
  z-index: 100;
  top: 0; left: 0;
  margin: auto;
}

＆＃39; .stick＆＃39;在满足某些条件时添加，从而激活它。一切都很完美，除非添加.stick类并设置高度和宽度动画，它是从左到右完成的。我希望它来自中心。当删除.stick类时，它会从中心缩小，不知道为什么

Answer 1

尝试从position:fixed删除#attach.stick。这应该允许它像你期望的那样扩展。

JSFiddle（点击框切换）

如果您需要position:fixed，请始终为#attach提供明确的保证金，并为保证金设置动画（Fiddle）：

#attach {
    height: 50px;
    width: 60%;
    margin: 0 20%;
    border-top: 1px solid #000;
    border-bottom: 1px solid #000;
    -webkit-transition: margin 0.35s ease, height 0.35s ease, width 0.35s ease;
    -moz-transition: margin 0.35s ease, height 0.35s ease, width 0.35s ease;
    -ms-transition: margin 0.35s ease, height 0.35s ease, width 0.35s ease;
    -o-transition: margin 0.35s ease, height 0.35s ease, width 0.35s ease;
    transition: margin 0.35s ease, height 0.35s ease, width 0.35s ease;
}

#attach.stick {
    height: 80px;
    width: 100%;
    border-bottom: 1px solid #000;
    background-color: rgba(250, 250, 250, 1);
    z-index: 100;
    top: 0;
    left:0;
    margin: 0;
    position:fixed;
}

从元素中心过渡宽度

1 个答案: