JS 联想自动补齐功能 - FACESOHO知行者

<!DOCTYPE html>
<html>
<head> 
<meta charset="UTF-8"> 
<title>JS 联想 自动补齐功能</title> 
</head>
<body>
<style>
* { box-sizing:border-box; }
body{font:16px Arial;}
.autocomplete{/*the container must be positioned relative:*/
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;}
.autocomplete-items{position:absolute;order:1px solid #d4d4d4;border-bottom:none;border-top:none;z-index:99;
/*position the autocomplete items to be the same width as the container:*/ top:100%;left:0;right:0;}
.autocomplete-items div{padding:10px;cursor:pointer;background-color:#fff; border-bottom:1px solid #d4d4d4;}
.autocomplete-items div:hover{/*when hovering an item:*/background-color:#e9e9e9;}
.autocomplete-active{/*when navigating through the items using the arrow keys:*/
background-color:DodgerBlue !important; color:#ffffff;}
</style>

<form autocomplete="off" action="/action_page.php">
<div class="autocomplete" style="width:300px;">
<input id="myInput" type="text" name="myCountry" placeholder="输入国家或地区英文名...">
</div>
<input type="submit">
</form>
<script>
function autocomplete(inp, arr) {/*函数主要有两个参数：文本框元素和自动补齐的完整数据*/
var currentFocus;/* 监听 - 在写入时触发 */
inp.addEventListener("input", function(e) {
var a, b, i, val = this.value;/*关闭已经打开的自动完成值列表*/
closeAllLists();
if (!val) { return false;}
currentFocus = -1;/*创建列表*/
a = document.createElement("DIV");
a.setAttribute("id", this.id + "autocomplete-list");
a.setAttribute("class", "autocomplete-items");/*添加 DIV 元素*/
this.parentNode.appendChild(a);/*循环数组...*/
for (i = 0; i < arr.length; i++) {/*检查选项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()) {/*为匹配元素创建 DIV*/
    b = document.createElement("DIV");/*使匹配字母变粗体*/
    b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>";
    b.innerHTML += arr[i].substr(val.length);/*insert a input field that will hold the current array item's value:*/
    b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>";/*execute a function when someone clicks on the item value (DIV element):*/
    b.addEventListener("click", function(e) {/*insert the value for the autocomplete text field:*/
        inp.value = this.getElementsByTagName("input")[0].value; /*close the list of autocompleted values,(or any other open lists of autocompleted values:*/
        closeAllLists();
    });
    a.appendChild(b);
  }
}
});
/*execute a function presses a key on the keyboard:*/
inp.addEventListener("keydown", function(e) {
var x = document.getElementById(this.id + "autocomplete-list");
if (x) x = x.getElementsByTagName("div");
if (e.keyCode == 40) {/*If the arrow DOWN key is pressed,increase the currentFocus variable:*/
  currentFocus++;/*and and make the current item more visible:*/
  addActive(x);
} else if (e.keyCode == 38) { //up /*If the arrow UP key is pressed, decrease the currentFocus variable:*/
  currentFocus--; /*and and make the current item more visible:*/
  addActive(x);
} else if (e.keyCode == 13) { /*If the ENTER key is pressed, prevent the form from being submitted,*/
  e.preventDefault();
  if (currentFocus > -1) {/*and simulate a click on the "active" item:*/
    if (x) x[currentFocus].click();
  }
}
});
function addActive(x) {/*a function to classify an item as "active":*/
if (!x) return false;/*start by removing the "active" class on all items:*/
removeActive(x);
if (currentFocus >= x.length) currentFocus = 0;
if (currentFocus < 0) currentFocus = (x.length - 1);/*add class "autocomplete-active":*/
x[currentFocus].classList.add("autocomplete-active");
}
function removeActive(x) {/*a function to remove the "active" class from all autocomplete items:*/
for (var i = 0; i < x.length; i++) {
x[i].classList.remove("autocomplete-active");
}
}
function closeAllLists(elmnt) {/*close all autocomplete lists in the document,except the one passed as an argument:*/
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]);
}
}
}
/*execute a function when someone clicks in the document:*/
document.addEventListener("click", function (e) {closeAllLists(e.target);});
}
/*数组 - 包含所有国家或地区名*/
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 China","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 China","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 China","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"];
/*传递参数*/
autocomplete(document.getElementById("myInput"), countries);
</script>
</body>
</html>