使用方法:

1.定義ResizeImg(obj)方法

 1 function ResizeImg(obj) {
 2     var boxHeight = $(".box").height();
 3     var boxWidth = $(".box").width();
 4     var imgHeight = $(obj).height();
 5     var imgWidth = $(obj).width();
 6     if (imgHeight * boxWidth >= imgWidth * boxHeight) {
 7         //
 
調整後,高度超出的情況
 8         var afterImgHeight = boxWidth * imgHeight / imgWidth;
 9         $(obj).css("width", boxWidth + "px").css("height", afterImgHeight + "px");
10         var offsetTop = (afterImgHeight / 2) - (boxHeight / 2);
11         $(obj).css("top", "-" + offsetTop + "px"); //  -20px
12     }
 
13     else {
14         //調整後,寬度超出的情況
15         var afterImgWidth = boxHeight * imgWidth / imgHeight;
16         $(obj).css("height", boxHeight + "px").css("width", afterImgWidth + "px");
17         var offsetLeft = (afterImgWidth / 2) - (boxWidth / 2);
18         $(obj).css("left", "-" + offsetLeft + "px"); //
 
  -20px
19     }
20     console.log("resize ok.");
21 }

2.在img標綁定onload事件處理方法為ResizeImg.

<img src="xxx.jpg" onload="ResizeImg(this)"/>

3.註意:

不設置圖片的寬,高;

需設置圖片定位屬性,position: relative;

效果如下圖:

js腳本控制圖片水平與垂直居中