background attachment: fixed not working on android/ios

Question

This is my code:

Answer 1

bacground-attachment:fixed;

 .fixed { 
    background: url(img/kid1/1.jpg) no-repeat center center;
    background-attachment:fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    }