如果宽度<高度使用Javascript旋转图像而不修改每个图像？

Question

我正在尝试将所有图像元素放在html页面上然后检查每个图像(如果width < height(纵向)然后旋转它).

问题是我的脚本不适用于每个图像,但对于所有图像,因为我通过"img"标签获取图像,然后我不知道如何应用单个图像的旋转.

是否可以在不必修改每个图像的标记的情况下执行此操作(我想避免为每个图像放置ID)？

<script>
$(document).ready(function() {
    var imgs = document.getElementsByTagName("img");

    for (var i = 0; i < imgs.length; i++) {
        img = document.getElementsByTagName("img")[i];
        var width = img.clientWidth;
        var height = img.clientHeight;
        if(width<height){
            img.setAttribute('style','transform:rotate(90deg)'); //how do I apply this for each image?
        }
        else{
        }
    }
});
</script>

Answer 1

您的代码似乎适用于正确尺寸的图像.但是,您可以稍微更改一下代码.对于您提供的代码,您不需要这样做:

img = document.getElementsByTagName("img")[i];

在每次迭代的for循环中,因为这是一个昂贵的函数来运行.相反,您已经document.getElementsByTagName("img");存储了存储的结果imgs,因此您可以使用它:

img = imgs[i];

见下面的工作示例:

$(document).ready(function() {
  var imgs = document.getElementsByTagName("img");
  var imgSrcs = [];

  for (var i = 0; i < imgs.length; i++) {
    img = imgs[i];
    var width = img.clientWidth;
    var height = img.clientHeight;
    if (width < height) {
      img.setAttribute('style', 'transform:rotate(90deg)'); 
    }
  };
});

img {
  height: 150px;
  width: auto;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<p>Width &gt; Height</p>
<img src="https://media.wired.com/photos/5926db217034dc5f91becd6b/master/w_1904,c_limit/so-logo-s.jpg" />

<p>Width &lt; Height</p>
<img src="https://d1qb2nb5cznatu.cloudfront.net/startups/i/32728-274244db60c65e1cc32abb4c54a2c582-medium_jpg.jpg?buster=1442602512" />

<p>Width &lt; Height</p>
<img src="https://images.unsplash.com/photo-1522092787785-60123fde65c4?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=94d6ebf03fdc6a3c8159ac9aeceb0483&w=1000&q=80" />

此外,由于您使用jQuery,使用jQuery方法可以更轻松地完成此操作:

$(document).ready(function() {
  $('img').each((_, elem) => {
    let width = $(elem).width();
    let height = $(elem).height();
    if(width < height) {
      $(elem).css({'transform': 'rotate(90deg)'});
    }
  });
});

img {
  height: 150px;
  width: auto;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<p>Width &gt; Height</p>
<img src="https://media.wired.com/photos/5926db217034dc5f91becd6b/master/w_1904,c_limit/so-logo-s.jpg" />

<p>Width &lt; Height</p>
<img src="https://d1qb2nb5cznatu.cloudfront.net/startups/i/32728-274244db60c65e1cc32abb4c54a2c582-medium_jpg.jpg?buster=1442602512" />

<p>Width &lt; Height</p>
<img src="https://images.unsplash.com/photo-1522092787785-60123fde65c4?ixlib=rb-0.3.5&ixid=eyJhcHBfaWQiOjEyMDd9&s=94d6ebf03fdc6a3c8159ac9aeceb0483&w=1000&q=80" />