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<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> * { box-sizing: border-box; } body { font: 16px Arial; } /*容器必须相对定位： */ .autocomplete { position: relative; display: inline-block; } input { border: 1px solid transparent; background-color: #f1f1f1; padding: 10px; font-size: 16px; } input[type=text] { background-color: #f1f1f1; width: 100%; } input[type=submit] { background-color: DodgerBlue; color: #fff; cursor: pointer; } .autocomplete-items { position: absolute; border: 1px solid #d4d4d4; border-bottom: none; border-top: none; z-index: 99; /* 将自动完成项定位为与容器相同的宽度： */ top: 100%; left: 0; right: 0; } .autocomplete-items div { padding: 10px; cursor: pointer; background-color: #fff; border-bottom: 1px solid #d4d4d4; } /* 当鼠标悬停在项目上时： */ .autocomplete-items div:hover { background-color: #e9e9e9; } /* 当使用箭头键浏览项目时：*/ .autocomplete-active { background-color: DodgerBlue !important; color: #ffffff; } </style> </head> <body> <h2>自动完成</h2> <p>请开始输入：</p> <!-- 确保表单已关闭自动完成功能： --> <form autocomplete="off" action="/demo/action_page.php"> <div class="autocomplete" style="width:300px;"> <input id="myInput" type="text" name="myCountry" placeholder="Country"> </div> <input type="submit"> </form> <script> function autocomplete(inp, arr) { /* 自动完成函数需要两个参数，一个是文本字段元素，另一个是可以自动完成的可能值的数组： */ var currentFocus; /* 当有人在文本字段中写入时执行的函数： */ inp.addEventListener("input", function(e) { var a, b, i, val = this.value; /* 关闭任何已经打开的自动完成值列表 */ closeAllLists(); if (!val) { return false;} currentFocus = -1; /* 创建一个包含项目（值）的 DIV 元素： */ a = document.createElement("DIV"); a.setAttribute("id", this.id + "autocomplete-list"); a.setAttribute("class", "autocomplete-items"); /* 将这个 DIV 元素附加为自动完成容器的子元素：*/ this.parentNode.appendChild(a); /* 遍历数组中的每个项目... */ for (i = 0; i < arr.length; i++) { /* 检查项目是否以与文本字段值相同的字母开头： */ if (arr[i].substr(0, val.length).toUpperCase() == val.toUpperCase()) { /* 为每个匹配元素创建一个 DIV 元素： */ b = document.createElement("DIV"); /* 将匹配的字母加粗： */ b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>"; b.innerHTML += arr[i].substr(val.length); /* 插入一个输入字段来保存当前数组项的值： */ b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>"; /* 当有人单击项目值（DIV 元素）时执行的函数： */ b.addEventListener("click", function(e) { /* 插入自动完成文本字段的值： */ inp.value = this.getElementsByTagName("input")[0].value; /*关闭自动完成值列表，或任何其他打开的自动完成值列表： */ closeAllLists(); }); a.appendChild(b); } } }); /* 当有人在键盘上按键时执行一个函数：*/ inp.addEventListener("keydown", function(e) { var x = document.getElementById(this.id + "autocomplete-list"); if (x) x = x.getElementsByTagName("div"); if (e.keyCode == 40) { /*如果按下箭头向下键，增加 currentFocus 变量：*/ currentFocus++; /* 并使当前项目更加明显：*/ addActive(x); } else if (e.keyCode == 38) { //up /* 如果按下向上箭头键，减少 currentFocus 变量：*/ currentFocus--; /* 并使当前项目更加明显：*/ addActive(x); } else if (e.keyCode == 13) { /* 如果按下 ENTER 键，则阻止提交表单：*/ e.preventDefault(); if (currentFocus > -1) { /* 并模拟点击“活动”项目：*/ if (x) x[currentFocus].click(); } } }); function addActive(x) { /* 将项目分类为“活动”的函数：*/ if (!x) return false; /* 首先删除所有项目中的 "active" 类：*/ removeActive(x); if (currentFocus >= x.length) currentFocus = 0; if (currentFocus < 0) currentFocus = (x.length - 1); /* 添加 "autocomplete-active" 类：*/ x[currentFocus].classList.add("autocomplete-active"); } function removeActive(x) { /* 从所有自动完成项中删除 "active" 类的函数：*/ for (var i = 0; i < x.length; i++) { x[i].classList.remove("autocomplete-active"); } } function closeAllLists(elmnt) { /*关闭文档中的所有自动完成列表，除了作为参数传递的那个：*/ var x = document.getElementsByClassName("autocomplete-items"); for (var i = 0; i < x.length; i++) { if (elmnt != x[i] && elmnt != inp) { x[i].parentNode.removeChild(x[i]); } } } /* 当有人单击文档时执行的函数*/ document.addEventListener("click", function (e) { closeAllLists(e.target); }); } /* 包含世界上所有国家/地区的数组： */ var countries = ["Afghanistan","Albania","Algeria","Andorra","Angola","Anguilla","Antigua & Barbuda","Argentina","Armenia","Aruba","Australia","Austria","Azerbaijan","Bahamas","Bahrain","Bangladesh","Barbados","Belarus","Belgium","Belize","Benin","Bermuda","Bhutan","Bolivia","Bosnia & Herzegovina","Botswana","Brazil","British Virgin Islands","Brunei","Bulgaria","Burkina Faso","Burundi","Cambodia","Cameroon","Canada","Cape Verde","Cayman Islands","Central Arfrican Republic","Chad","Chile","China","Colombia","Congo","Cook Islands","Costa Rica","Cote D Ivoire","Croatia","Cuba","Curacao","Cyprus","Czech Republic","Denmark","Djibouti","Dominica","Dominican Republic","Ecuador","Egypt","El Salvador","Equatorial Guinea","Eritrea","Estonia","Ethiopia","Falkland Islands","Faroe Islands","Fiji","Finland","France","French Polynesia","French West Indies","Gabon","Gambia","Georgia","Germany","Ghana","Gibraltar","Greece","Greenland","Grenada","Guam","Guatemala","Guernsey","Guinea","Guinea Bissau","Guyana","Haiti","Honduras","Hong Kong","Hungary","Iceland","India","Indonesia","Iran","Iraq","Ireland","Isle of Man","Israel","Italy","Jamaica","Japan","Jersey","Jordan","Kazakhstan","Kenya","Kiribati","Kosovo","Kuwait","Kyrgyzstan","Laos","Latvia","Lebanon","Lesotho","Liberia","Libya","Liechtenstein","Lithuania","Luxembourg","Macau","Macedonia","Madagascar","Malawi","Malaysia","Maldives","Mali","Malta","Marshall Islands","Mauritania","Mauritius","Mexico","Micronesia","Moldova","Monaco","Mongolia","Montenegro","Montserrat","Morocco","Mozambique","Myanmar","Namibia","Nauro","Nepal","Netherlands","Netherlands Antilles","New Caledonia","New Zealand","Nicaragua","Niger","Nigeria","North Korea","Norway","Oman","Pakistan","Palau","Palestine","Panama","Papua New Guinea","Paraguay","Peru","Philippines","Poland","Portugal","Puerto Rico","Qatar","Reunion","Romania","Russia","Rwanda","Saint Pierre & Miquelon","Samoa","San Marino","Sao Tome and Principe","Saudi Arabia","Senegal","Serbia","Seychelles","Sierra Leone","Singapore","Slovakia","Slovenia","Solomon Islands","Somalia","South Africa","South Korea","South Sudan","Spain","Sri Lanka","St Kitts & Nevis","St Lucia","St Vincent","Sudan","Suriname","Swaziland","Sweden","Switzerland","Syria","Taiwan","Tajikistan","Tanzania","Thailand","Timor L'Este","Togo","Tonga","Trinidad & Tobago","Tunisia","Turkey","Turkmenistan","Turks & Caicos","Tuvalu","Uganda","Ukraine","United Arab Emirates","United Kingdom","United States of America","Uruguay","Uzbekistan","Vanuatu","Vatican City","Venezuela","Vietnam","Virgin Islands (US)","Yemen","Zambia","Zimbabwe"]; /* 在“myInput”元素上初始化自动完成功能，并将 countries 数组作为可能的自动完成值传递： */ autocomplete(document.getElementById("myInput"), countries); </script> </body> </html>