<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body {
            font-family: "Microsoft YaHei", serif;
        }

        body, dl, dd, p, h1, h2, h3, h4, h5, h6 {
            margin: 0;
        }

        ol, ul, li {
            margin: 0;
            padding: 0;
            list-style: none;
        }

        img {
            border: none
        }
    </style>
</head>
<body>

<script>
    function a(x,y) {
        console.log(x);
        console.log(y);
        console.log(this);
    }
    function b(x) {
        x(7,5);
    }

    // a.bind(document);这样直接写是没有什么效果的

    b(a.bind(document));


    a.bind(10)(7,5);

    var z = a.bind(document);
    z();
</script>
</body>
</html>