mask和background用法是相仿的，mask的值有这些

    image.png

    1. mask-clip
    2. mask-composite
    3. mask-image
    4. mask-mode
    5. mask-origin
    6. mask-position
    7. mask-repeat
    8. mask-size
    9. mask-type
    1. <!doctype html>
    2. <html lang="en">
    3.  <head>
    4.   <meta charset="UTF-8">
    6.   <style>
    7.     .mask{
    8.         width:475px;
    9.         height:260px;
    10.         background-image:url("http://img.blog.csdn.net/20170701221659356");
    12.         /* 取值是图片路径 */
    13.         -webkit-mask-image:url("http://img.blog.csdn.net/20170701221732018");
    14.     }
    15.   </style>
    16.  </head>
    17.  <body>
    18.     <div class="mask"> </div>
    19.  </body>
    21. </html>