Greasy Fork

或者用百度的免费api也行，只是要申请一下服务，替换下 appid 和 key 就行

// ==UserScript==
// @name         划词翻译（百度版）
// @namespace    https://greasyfork.org/zh-CN/users/150560
// @version      1.0.0
// @description  划词翻译
// @author       xinggsf
// @include      http*
// @run-at       document-start
// @connect      fanyi-api.baidu.com
// @connect      api.fanyi.baidu.com
// @grant        GM_xmlhttpRequest
// ==/UserScript==

'use strict';
const languageUrl = 'https://fanyi-api.baidu.com/api/trans/vip/language';
const transUrl = 'http://api.fanyi.baidu.com/api/trans/vip/translate';
const appid = '自备';
const key = '自备';

// 翻译结果面板
class TranslateTip {
    constructor() {
        const div = document.createElement('div');
        div.hidden = true;
        div.setAttribute('style',
`position:absolute!important;
font-size:13px!important;
overflow:auto!important;
background:#fff!important;
font-family:sans-serif,Arial!important;
font-weight:normal!important;
text-align:left!important;
color:#000!important;
padding:0.5em 1em!important;
line-height:1.5em!important;
border-radius:5px!important;
border:1px solid #ccc!important;
box-shadow:4px 4px 8px #888!important;
max-width:350px!important;
max-height:216px!important;
z-index:2147483647!important;`
        );
        document.documentElement.appendChild(div);
        //点击了翻译内容面板，不再创建翻译图标
        div.addEventListener('mouseup', e => e.stopPropagation());
        this._tip = div;
    }
    showText(text) { //显示翻译文本
        this._tip.innerHTML = text;
        this._tip.hidden = !1;
    }
    hide() {
        this._tip.innerHTML = '';
        this._tip.hidden = true;
    }
    pop(ev) {
        this._tip.style.top = ev.pageY + 'px';
        //面板最大宽度为350px
        this._tip.style.left = (ev.pageX + 350 <= document.body.clientWidth ?
            ev.pageX : document.body.clientWidth - 350) + 'px';
    }
}
const tip = new TranslateTip();

class Icon {
    constructor() {
        const icon = document.createElement('span');
        icon.hidden = true;
        icon.innerHTML = `<svg style="margin:4px !important;" "width="24" height="24" viewBox="0 0 768 768">
            <path d="M672 640.5v-417c0-18-13.5-31.5-31.5-31.5h-282l37.5 129h61.5v-33h34.5v33h115.5v33h-40.5c-10.5 40.5-33 79.5-61.5 112.5l87 85.5-22.5 24-87-85.5-28.5 28.5 25.5 88.5-64.5 64.5h225c18 0 31.5-13.5 31.5-31.5zM447 388.5c7.5 15 19.5 34.5 36 54 39-46.5 49.5-88.5 49.5-88.5h-127.5l10.5 34.5h31.5zM423 412.5l19.5 70.5 18-16.5c-15-16.5-27-34.5-37.5-54zM355.5 339c0-7.381-0.211-16.921-3-22.5h-126v49.5h70.5c-4.5 19.5-24 48-67.5 48-42 0-76.5-36-76.5-78s34.5-78 76.5-78c24 0 39 10.5 48 19.5l3 1.5 39-37.5-3-1.5c-24-22.5-54-34.5-87-34.5-72 0-130.5 58.5-130.5 130.5s58.5 130.5 130.5 130.5c73.5 0 126-52.5 126-127.5zM640.5 160.5c34.5 0 63 28.5 63 63v417c0 34.5-28.5 63-63 63h-256.5l-31.5-96h-225c-34.5 0-63-28.5-63-63v-417c0-34.5 28.5-63 63-63h192l28.5 96h292.5z" style="fill:#3e84f4;"></svg>`;
        icon.setAttribute('style',
        `width:32px!important;
        height:32px!important;
        background:#fff!important;
        border-radius:50%!important;
        box-shadow:4px 4px 8px #888!important;
        position:absolute!important;
        z-index:2147483647!important;`
        );
        document.documentElement.appendChild(icon);
        //拦截二个鼠标事件，以防止选中的文本消失
        icon.addEventListener('mousedown', e => e.preventDefault(), true);
        icon.addEventListener('mouseup', ev => ev.preventDefault(), true);
        icon.addEventListener('click', ev => {
            if (ev.ctrlKey) navigator.clipboard.readText()
                .then(text => {
                    this.queryText(text.trim(),ev);
                })
                .catch(err => {
                    console.error('Failed to read clipboard contents: ', err);
                });
            else {
                const text = window.getSelection().toString().trim().replace(/\s{2,}/g, ' ');
                this.queryText(text,ev);
            }
        });
        this._icon = icon;
    }
    pop(ev) {
        const icon = this._icon;
        icon.style.top = ev.pageY + 12 + 'px';
        icon.style.left = ev.pageX + 'px';
        icon.hidden = !1;
        setTimeout(this.hide.bind(this), 2e3);
    }
    hide() {
        this._icon.hidden = true;
    }
    queryText(text,ev) {
        if (text) {
            this._icon.hidden = true;
            tip.pop(ev);
            translate(text);
        }
    }
}
const icon = new Icon();

document.addEventListener('mouseup', function(e) {
    var text = window.getSelection().toString().trim();
    if (!text) {
        icon.hide();
        tip.hide();
    }
    else icon.pop(e);
});

function translate(text) {
    console.log(text);
    var salt = (new Date).getTime();
    var str1 = appid + text + salt + key;
    var sign = md5(str1);
    GM_xmlhttpRequest({
        method: 'POST',
        responseType: 'json',
        url: languageUrl,
        data: "appid=" + appid + "&salt=" + salt + "&sign=" + sign + "&q=" + encodeURIComponent(text),
        headers: { "Content-Type": "application/x-www-form-urlencoded" },
        onload: function(res) {
            var response = res.response;
            var language = "auto";
            var to = "zh";
            if(response.error_code === 0){
                language = response.data.src;
                console.log("语种识别结果：" + language);
                if("zh" === language){
                    to = "en";
                }
            }else{
                console.log("语种识别失败，已设置为auto\n返回结果: "+ JSON.stringify(response));
            }
            doTranslate(text, language, to);
            return;
        },
        onerror: function(res) {
            var response = res.response;
            console.log(response);
            tip.showText("语种识别失败\n返回结果: "+ JSON.stringify(response));
        }
    });
}

function doTranslate(text, from, to) {
    var salt = (new Date).getTime();
    var str1 = appid + text + salt + key;
    var sign = md5(str1);
    GM_xmlhttpRequest({
        method: 'POST',
        responseType: 'json',
        url: transUrl,
        data: "appid=" + appid + "&from=" + from + "&to=" + to + "&salt=" + salt + "&sign=" + sign + "&q=" + encodeURIComponent(text),
        headers: { "Content-Type": "application/x-www-form-urlencoded" },
        onload: function(res) {
            var response = res.response;
            if(response && response.trans_result){
                var result = response.trans_result.map(el => el.dst).join('<br />');
                tip.showText(result);
                return;
            }
            console.log(response);
            tip.showText("翻译失败\n返回结果: "+ JSON.stringify(response));
        },
        onerror: function(res) {
            var response = res.response;
            console.log(response);
            tip.showText("翻译失败\n返回结果: "+ JSON.stringify(response));
        }
    });
}

function md5(string) {
    function RotateLeft(lValue, iShiftBits) {
        return (lValue<<iShiftBits) | (lValue>>>(32-iShiftBits));
    }
    function AddUnsigned(lX,lY) {
        var lX4,lY4,lX8,lY8,lResult;
        lX8 = (lX & 0x80000000);
        lY8 = (lY & 0x80000000);
        lX4 = (lX & 0x40000000);
        lY4 = (lY & 0x40000000);
        lResult = (lX & 0x3FFFFFFF)+(lY & 0x3FFFFFFF);
        if (lX4 & lY4) {
            return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
        }
        if (lX4 | lY4) {
            if (lResult & 0x40000000) {
                return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
            } else {
                return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
            }
        } else {
            return (lResult ^ lX8 ^ lY8);
        }
    }
    function F(x,y,z) { return (x & y) | ((~x) & z); }
    function G(x,y,z) { return (x & z) | (y & (~z)); }
    function H(x,y,z) { return (x ^ y ^ z); }
    function I(x,y,z) { return (y ^ (x | (~z))); }

    function FF(a,b,c,d,x,s,ac) {
        a = AddUnsigned(a, AddUnsigned(AddUnsigned(F(b, c, d), x), ac));
        return AddUnsigned(RotateLeft(a, s), b);
    };

    function GG(a,b,c,d,x,s,ac) {
        a = AddUnsigned(a, AddUnsigned(AddUnsigned(G(b, c, d), x), ac));
        return AddUnsigned(RotateLeft(a, s), b);
    };

    function HH(a,b,c,d,x,s,ac) {
        a = AddUnsigned(a, AddUnsigned(AddUnsigned(H(b, c, d), x), ac));
        return AddUnsigned(RotateLeft(a, s), b);
    };

    function II(a,b,c,d,x,s,ac) {
        a = AddUnsigned(a, AddUnsigned(AddUnsigned(I(b, c, d), x), ac));
        return AddUnsigned(RotateLeft(a, s), b);
    };

    function ConvertToWordArray(string) {
        var lWordCount;
        var lMessageLength = string.length;
        var lNumberOfWords_temp1=lMessageLength + 8;
        var lNumberOfWords_temp2=(lNumberOfWords_temp1-(lNumberOfWords_temp1 % 64))/64;
        var lNumberOfWords = (lNumberOfWords_temp2+1)*16;
        var lWordArray=Array(lNumberOfWords-1);
        var lBytePosition = 0;
        var lByteCount = 0;
        while ( lByteCount < lMessageLength ) {
            lWordCount = (lByteCount-(lByteCount % 4))/4;
            lBytePosition = (lByteCount % 4)*8;
            lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount)<<lBytePosition));
            lByteCount++;
        }
        lWordCount = (lByteCount-(lByteCount % 4))/4;
        lBytePosition = (lByteCount % 4)*8;
        lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80<<lBytePosition);
        lWordArray[lNumberOfWords-2] = lMessageLength<<3;
        lWordArray[lNumberOfWords-1] = lMessageLength>>>29;
        return lWordArray;
    };

    function WordToHex(lValue) {
        var WordToHexValue="",WordToHexValue_temp="",lByte,lCount;
        for (lCount = 0;lCount<=3;lCount++) {
            lByte = (lValue>>>(lCount*8)) & 255;
            WordToHexValue_temp = "0" + lByte.toString(16);
            WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length-2,2);
        }
        return WordToHexValue;
    };

    function Utf8Encode(string) {
        string = string.replace(/\r\n/g,"\n");
        var utftext = "";

        for (var n = 0; n < string.length; n++) {

            var c = string.charCodeAt(n);

            if (c < 128) {
                utftext += String.fromCharCode(c);
            }
            else if((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192);
                utftext += String.fromCharCode((c & 63) | 128);
            }
            else {
                utftext += String.fromCharCode((c >> 12) | 224);
                utftext += String.fromCharCode(((c >> 6) & 63) | 128);
                utftext += String.fromCharCode((c & 63) | 128);
            }

        }

        return utftext;
    };

    var x=Array();
    var k,AA,BB,CC,DD,a,b,c,d;
    var S11=7, S12=12, S13=17, S14=22;
    var S21=5, S22=9 , S23=14, S24=20;
    var S31=4, S32=11, S33=16, S34=23;
    var S41=6, S42=10, S43=15, S44=21;

    string = Utf8Encode(string);

    x = ConvertToWordArray(string);

    a = 0x67452301; b = 0xEFCDAB89; c = 0x98BADCFE; d = 0x10325476;

    for (k=0;k<x.length;k+=16) {
        AA=a; BB=b; CC=c; DD=d;
        a=FF(a,b,c,d,x[k+0], S11,0xD76AA478);
        d=FF(d,a,b,c,x[k+1], S12,0xE8C7B756);
        c=FF(c,d,a,b,x[k+2], S13,0x242070DB);
        b=FF(b,c,d,a,x[k+3], S14,0xC1BDCEEE);
        a=FF(a,b,c,d,x[k+4], S11,0xF57C0FAF);
        d=FF(d,a,b,c,x[k+5], S12,0x4787C62A);
        c=FF(c,d,a,b,x[k+6], S13,0xA8304613);
        b=FF(b,c,d,a,x[k+7], S14,0xFD469501);
        a=FF(a,b,c,d,x[k+8], S11,0x698098D8);
        d=FF(d,a,b,c,x[k+9], S12,0x8B44F7AF);
        c=FF(c,d,a,b,x[k+10],S13,0xFFFF5BB1);
        b=FF(b,c,d,a,x[k+11],S14,0x895CD7BE);
        a=FF(a,b,c,d,x[k+12],S11,0x6B901122);
        d=FF(d,a,b,c,x[k+13],S12,0xFD987193);
        c=FF(c,d,a,b,x[k+14],S13,0xA679438E);
        b=FF(b,c,d,a,x[k+15],S14,0x49B40821);
        a=GG(a,b,c,d,x[k+1], S21,0xF61E2562);
        d=GG(d,a,b,c,x[k+6], S22,0xC040B340);
        c=GG(c,d,a,b,x[k+11],S23,0x265E5A51);
        b=GG(b,c,d,a,x[k+0], S24,0xE9B6C7AA);
        a=GG(a,b,c,d,x[k+5], S21,0xD62F105D);
        d=GG(d,a,b,c,x[k+10],S22,0x2441453);
        c=GG(c,d,a,b,x[k+15],S23,0xD8A1E681);
        b=GG(b,c,d,a,x[k+4], S24,0xE7D3FBC8);
        a=GG(a,b,c,d,x[k+9], S21,0x21E1CDE6);
        d=GG(d,a,b,c,x[k+14],S22,0xC33707D6);
        c=GG(c,d,a,b,x[k+3], S23,0xF4D50D87);
        b=GG(b,c,d,a,x[k+8], S24,0x455A14ED);
        a=GG(a,b,c,d,x[k+13],S21,0xA9E3E905);
        d=GG(d,a,b,c,x[k+2], S22,0xFCEFA3F8);
        c=GG(c,d,a,b,x[k+7], S23,0x676F02D9);
        b=GG(b,c,d,a,x[k+12],S24,0x8D2A4C8A);
        a=HH(a,b,c,d,x[k+5], S31,0xFFFA3942);
        d=HH(d,a,b,c,x[k+8], S32,0x8771F681);
        c=HH(c,d,a,b,x[k+11],S33,0x6D9D6122);
        b=HH(b,c,d,a,x[k+14],S34,0xFDE5380C);
        a=HH(a,b,c,d,x[k+1], S31,0xA4BEEA44);
        d=HH(d,a,b,c,x[k+4], S32,0x4BDECFA9);
        c=HH(c,d,a,b,x[k+7], S33,0xF6BB4B60);
        b=HH(b,c,d,a,x[k+10],S34,0xBEBFBC70);
        a=HH(a,b,c,d,x[k+13],S31,0x289B7EC6);
        d=HH(d,a,b,c,x[k+0], S32,0xEAA127FA);
        c=HH(c,d,a,b,x[k+3], S33,0xD4EF3085);
        b=HH(b,c,d,a,x[k+6], S34,0x4881D05);
        a=HH(a,b,c,d,x[k+9], S31,0xD9D4D039);
        d=HH(d,a,b,c,x[k+12],S32,0xE6DB99E5);
        c=HH(c,d,a,b,x[k+15],S33,0x1FA27CF8);
        b=HH(b,c,d,a,x[k+2], S34,0xC4AC5665);
        a=II(a,b,c,d,x[k+0], S41,0xF4292244);
        d=II(d,a,b,c,x[k+7], S42,0x432AFF97);
        c=II(c,d,a,b,x[k+14],S43,0xAB9423A7);
        b=II(b,c,d,a,x[k+5], S44,0xFC93A039);
        a=II(a,b,c,d,x[k+12],S41,0x655B59C3);
        d=II(d,a,b,c,x[k+3], S42,0x8F0CCC92);
        c=II(c,d,a,b,x[k+10],S43,0xFFEFF47D);
        b=II(b,c,d,a,x[k+1], S44,0x85845DD1);
        a=II(a,b,c,d,x[k+8], S41,0x6FA87E4F);
        d=II(d,a,b,c,x[k+15],S42,0xFE2CE6E0);
        c=II(c,d,a,b,x[k+6], S43,0xA3014314);
        b=II(b,c,d,a,x[k+13],S44,0x4E0811A1);
        a=II(a,b,c,d,x[k+4], S41,0xF7537E82);
        d=II(d,a,b,c,x[k+11],S42,0xBD3AF235);
        c=II(c,d,a,b,x[k+2], S43,0x2AD7D2BB);
        b=II(b,c,d,a,x[k+9], S44,0xEB86D391);
        a=AddUnsigned(a,AA);
        b=AddUnsigned(b,BB);
        c=AddUnsigned(c,CC);
        d=AddUnsigned(d,DD);
    }

    var temp = WordToHex(a)+WordToHex(b)+WordToHex(c)+WordToHex(d);

    return temp.toLowerCase();
}