您可以使用箭头选择div。输入像＆＃39; k＆＃39; div开始溢出。我希望.autocomplete-items具有x个div的最大高度，这样任何一个都不能显示为一半，并且在使用箭头时需要向下/向上滚动，滚动的数量必须是等于即将出现的div的高度
function autocomplete(inp, arr) {
let currentFocus;
inp.addEventListener("input", function (e) {
let a, b, i, val = this.value;
closeAllLists();
if (!val) {
return false;
}
currentFocus = -1;
a = document.createElement("DIV");
a.setAttribute("id", this.id + "autocomplete-list");
a.setAttribute("class", "autocomplete-items");
this.parentNode.appendChild(a);
for (i = 0; i < arr.length; i++) {
if (arr[i].substr(0, val.length).toUpperCase() == val.toUpperCase()) {
b = document.createElement("DIV");
b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>";
b.innerHTML += arr[i].substr(val.length);
b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>";
b.addEventListener("click", function (e) {
inp.value = this.getElementsByTagName("input")[0].value;
closeAllLists();
});
a.appendChild(b);
}
}
});
inp.addEventListener("keydown", function (e) {
let x = document.getElementById(this.id + "autocomplete-list");
if (x) x = x.getElementsByTagName("div");
if (e.keyCode == 40) {
currentFocus++;
addActive(x);
} else if (e.keyCode == 38) {
currentFocus--;
addActive(x);
} else if (e.keyCode == 13) {
e.preventDefault();
if (currentFocus > -1) {
if (x) x[currentFocus].click();
}
}
});
function addActive(x) {
if (!x) return false;
removeActive(x);
if (currentFocus >= x.length) currentFocus = 0;
if (currentFocus < 0) currentFocus = (x.length - 1);
x[currentFocus].classList.add("autocomplete-active");
}
function removeActive(x) {
for (let i = 0; i < x.length; i++) {
x[i].classList.remove("autocomplete-active");
}
}
function closeAllLists(elmnt) {
let x = document.getElementsByClassName("autocomplete-items");
for (let i = 0; i < x.length; i++) {
if (elmnt != x[i] && elmnt != inp) {
x[i].parentNode.removeChild(x[i]);
}
}
}
document.addEventListener("click", function (e) {
closeAllLists(e.target);
});
}
function main(){
let 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"];
let searchBox = document.getElementById('searchBox');
autocomplete(searchBox, countries);
}body{
background: Navy;
}
form {
display: inline-block;
position: relative;
top: 0px;
right: 0px;
height: auto;
width: 128px;
padding: 0px;
}
.autocomplete-items > div:hover,
.autocomplete-active {
background-color: #fff!important;
color: #000!important;
}
#searchBox:focus {
outline: none;
}
#searchBox {
width: 118px;
height: 32px;
padding: 0px 5px 0px 5px;
border: 0px;
font-size: 13px;
text-transform: capitalize;
float: left;
}
.autocomplete-items {
position: absolute;
border-bottom: none;
border-top: none;
z-index: 99;
top: 100%;
left: 0;
right: 0;
max-height: 150px;
overflow-x: auto;
}
.autocomplete-items > div {
text-transform: uppercase;
background: #202020;
color: #fff;
padding: 10px;
cursor: pointer;
}<html>
<body onload="main();">
<form>
<input id="searchBox" placeholder="type country name">
</form>
<body>
<html>
答案 0 :(得分：0)
您可以通过衡量有关列表offsetTop＆amp;的活跃元素clientHeight和clientHeight来实现此目的。 scrollTop。
function scrollToActiveIfNecessary(x){
var active_element = x[currentFocus]
var container = active_element.parentNode
var offset = active_element.offsetTop // get element's y position in list
offset -= container.scrollTop // subtract list's scroll position to get relative position
var delta_to_bottom = offset+active_element.clientHeight - container.clientHeight // calculate distance from active element's bottom to the list's bottom
if(delta_to_bottom>0) // if distance is greater than 0, it must be out of view
container.scrollTop += delta_to_bottom // add delta to view
// same goes for top
var delta_to_top = offset
if(delta_to_top<0)
container.scrollTop += delta_to_top
}
function autocomplete(inp, arr) {
let currentFocus;
inp.addEventListener("input", function (e) {
let a, b, i, val = this.value;
closeAllLists();
if (!val) {
return false;
}
currentFocus = -1;
a = document.createElement("DIV");
a.setAttribute("id", this.id + "autocomplete-list");
a.setAttribute("class", "autocomplete-items");
this.parentNode.appendChild(a);
for (i = 0; i < arr.length; i++) {
if (arr[i].substr(0, val.length).toUpperCase() == val.toUpperCase()) {
b = document.createElement("DIV");
b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>";
b.innerHTML += arr[i].substr(val.length);
b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>";
b.addEventListener("click", function (e) {
inp.value = this.getElementsByTagName("input")[0].value;
closeAllLists();
});
a.appendChild(b);
}
}
});
inp.addEventListener("keydown", function (e) {
let x = document.getElementById(this.id + "autocomplete-list");
if (x) x = x.getElementsByTagName("div");
if (e.keyCode == 40) {
currentFocus++;
addActive(x);
} else if (e.keyCode == 38) {
currentFocus--;
addActive(x);
} else if (e.keyCode == 13) {
e.preventDefault();
if (currentFocus > -1) {
if (x) x[currentFocus].click();
}
}
});
function addActive(x) {
if (!x) return false;
removeActive(x);
if (currentFocus >= x.length) currentFocus = 0;
if (currentFocus < 0) currentFocus = (x.length - 1);
x[currentFocus].classList.add("autocomplete-active");
scrollToActiveIfNecessary(x)
}
function scrollToActiveIfNecessary(x){
var active_element = x[currentFocus]
var container = active_element.parentNode
var offset = active_element.offsetTop // get element's y position in list
offset -= container.scrollTop // subtract list's scroll position to get relative position
var delta_to_bottom = offset+active_element.clientHeight - container.clientHeight // calculate distance from active element's bottom to the list's bottom
if(delta_to_bottom>0) // if distance is greater than 0, it must be out of view
container.scrollTop += delta_to_bottom // add delta to view
// same goes for top
var delta_to_top = offset
if(delta_to_top<0)
container.scrollTop += delta_to_top
}
function removeActive(x) {
for (let i = 0; i < x.length; i++) {
x[i].classList.remove("autocomplete-active");
}
}
function closeAllLists(elmnt) {
let x = document.getElementsByClassName("autocomplete-items");
for (let i = 0; i < x.length; i++) {
if (elmnt != x[i] && elmnt != inp) {
x[i].parentNode.removeChild(x[i]);
}
}
}
document.addEventListener("click", function (e) {
closeAllLists(e.target);
});
}
function main(){
let 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"];
let searchBox = document.getElementById('searchBox');
autocomplete(searchBox, countries);
}body{
background: Navy;
}
form {
display: inline-block;
position: relative;
top: 0px;
right: 0px;
height: auto;
width: 128px;
padding: 0px;
}
.autocomplete-items > div:hover,
.autocomplete-active {
background-color: #fff!important;
color: #000!important;
}
#searchBox:focus {
outline: none;
}
#searchBox {
width: 118px;
height: 32px;
padding: 0px 5px 0px 5px;
border: 0px;
font-size: 13px;
text-transform: capitalize;
float: left;
}
.autocomplete-items {
position: absolute;
border-bottom: none;
border-top: none;
z-index: 99;
top: 100%;
left: 0;
right: 0;
max-height: 150px;
overflow-x: auto;
}
.autocomplete-items > div {
text-transform: uppercase;
background: #202020;
color: #fff;
padding: 10px;
cursor: pointer;
}<html>
<body onload="main();">
<form>
<input id="searchBox" placeholder="type country name">
</form>
<body>
<html>