JS 杂项

false

text="aaaa1111"

"aaaa1111"

pattern=/\d+/g//

/\d+/g

text.search(pattern)

4

text.match(pattern)

Array [ "1111" ]

text.replace(pattern,"2222")

"aaaa2222"

text.split(/\D+/)

Array [ "", "1111" ]

0!==0
false
null!=undefined
false
null!==undefined
true
null==undefined
true
null===undefined
false

var s="1111";
function f(){
    console.log(s)
    var s='2222'
    console.log(s)
}

<!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>
    <script>
        var fn = null;
          function f(e, t) {
            var r, n;
            r = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
                n = {
                    rotl: function (e, t) {
                        debugger
                        return e << t | e >>> 32 - t
                    },
                    rotr: function (e, t) {
                        return e << 32 - t | e >>> t
                    },
                    endian: function (e) {
                        if (e.constructor == Number)
                            return 16711935 & n.rotl(e, 8) | 4278255360 & n.rotl(e, 24);
                        for (var t = 0; t < e.length; t++)
                            e[t] = n.endian(e[t]);
                        return e
                    },
                    randomBytes: function (e) {
                        for (var t = []; e > 0; e--)
                            t.push(Math.floor(256 * Math.random()));
                        return t
                    },
                    bytesToWords: function (e) {
                        for (var t = [], r = 0, n = 0; r < e.length; r++,
                            n += 8)
                            t[n >>> 5] |= e[r] << 24 - n % 32;
                        return t
                    },
                    wordsToBytes: function (e) {
                        for (var t = [], r = 0; r < 32 * e.length; r += 8)
                            t.push(e[r >>> 5] >>> 24 - r % 32 & 255);
                        return t
                    },
                    bytesToHex: function (e) {
                        for (var t = [], r = 0; r < e.length; r++)
                            t.push((e[r] >>> 4).toString(16)),
                                t.push((15 & e[r]).toString(16));
                        return t.join("")
                    },
                    hexToBytes: function (e) {
                        for (var t = [], r = 0; r < e.length; r += 2)
                            t.push(parseInt(e.substr(r, 2), 16));
                        return t
                    },
                    bytesToBase64: function (e) {
                        for (var t = [], n = 0; n < e.length; n += 3)
                            for (var a = e[n] << 16 | e[n + 1] << 8 | e[n + 2], i = 0; i < 4; i++)
                                8 * n + 6 * i <= 8 * e.length ? t.push(r.charAt(a >>> 6 * (3 - i) & 63)) : t.push("=");
                        return t.join("")
                        }
                    }
                    debugger
                    fn = n.rotl;
        }
        f();
        fn(1,2);
    </script>
</body>
</html>

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