test.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div class="container">
        <div class="part" style="background: red;">afsadfsdfsdklfjslkdjfksjdfsdlkfjlskajdkfsd fjasdkljfkasjdkfjasdkjfkas
            dfjsadkjfkasdjfkjsdjfads</div>
        <div class="part" style="background: greenyellow;"></div>
        <div class="part" style="background: blue;"></div>
    </div>
    <style>
        .container {
            display: flex;
            width: 100%;
            height: 100vh;
        }

        .part {
            /* 元素无内容时，可以用flex-grow:1; 有内容需加上flex-basis:0; */
            flex-grow: 1;
            flex-basis: 0;
        }
    </style>
    <script>
        var obj = {
            a: 1,
            b: 2,
        }
        Object.prototype.c = function () {
            console.log('c');
        }
        for (var key in obj) {
            console.log(key)
        }
    </script>
</body>

</html>