javascript - 需要使用箭头键在搜索建议中移动

Question

我有一个带有很好建议的搜索栏，我需要能够使用箭头键在选项中移动，但它不起作用，我真的很困惑，请你能帮帮我吗，我一直几天来一直在与这些东西作斗争。

var searchIndex = ["404 Error", "Address Bar", "Ajax", "Apache", "Autoresponder", "BitTorrent", "Blog", "Bookmark", "Bot", "Broadband", "Captcha", "Certificate", "Client", "Cloud", "Cloud Computing", "CMS", "Cookie", "CSS", "Cyberspace", "Denial of Service", "DHCP", "Dial-up", "DNS Record", "Domain Name", "Download", "E-mail", "Facebook", "FiOS", "Firewall", "FTP", "Gateway", "Google", "Google Drive", "Gopher", "Hashtag", "Hit", "Home Page", "HTML", "HTTP", "HTTPS", "Hyperlink", "Hypertext", "ICANN", "Inbox", "Internet", "InterNIC", "IP", "IP Address", "IPv4", "IPv6", "IRC", "iSCSI", "ISDN", "ISP", "JavaScript", "jQuery", "Meta Search Engine", "Meta Tag", "Minisite", "Mirror", "Name Server", "Packet", "Page View", "Payload", "Phishing", "POP3", "Protocol", "Scraping", "Search Engine", "Social Networking", "Socket", "Spam", "Spider", "Spoofing", "SSH", "SSL", "Static Website", "Twitter", "XHTML"];

var input = document.getElementById("searchBox"),
  ul = document.getElementById("searchResults"),
  inputTerms, termsArray, prefix, terms, results, sortedResults;


var search = function() {
  inputTerms = input.value.toLowerCase();
  results = [];
  termsArray = inputTerms.split(' ');
  prefix = termsArray.length === 1 ? '' : termsArray.slice(0, -1).join(' ') + ' ';
  terms = termsArray[termsArray.length - 1].toLowerCase();

  for (var i = 0; i < searchIndex.length; i++) {
    var a = searchIndex[i].toLowerCase(),
      t = a.indexOf(terms);

    if (t > -1) {
      results.push(a);
    }
  }

  evaluateResults();
};

var evaluateResults = function() {
  if (results.length > 0 && inputTerms.length > 0 && terms.length !== 0) {
    sortedResults = results.sort(sortResults);
    appendResults();
  } else if (inputTerms.length > 0 && terms.length !== 0) {
    ul.innerHTML = '<li>Whoah! <strong>' +
      inputTerms +
      '</strong> is not in the index. <br><small><a href="http://google.com/search?q=' +
      encodeURIComponent(inputTerms) + '">Try Google?</a></small></li>';

  } else if (inputTerms.length !== 0 && terms.length === 0) {
    return;
  } else {
    clearResults();
  }
};

var sortResults = function(a, b) {
  if (a.indexOf(terms) < b.indexOf(terms)) return -1;
  if (a.indexOf(terms) > b.indexOf(terms)) return 1;
  return 0;
}

var appendResults = function() {
  clearResults();

  for (var i = 0; i < sortedResults.length && i < 5; i++) {
    var li = document.createElement("li"),
      result = prefix +
      sortedResults[i].toLowerCase().replace(terms, '<strong>'+ terms + '</strong>');

    li.innerHTML = result;

    ul.appendChild(li);
  }
  $('li').click(function(e) {
    $('input').val($(this).text());
  });
  if (ul.className !== "term-list") {
    ul.className = "term-list";
  }
};

var clearResults = function() {
  ul.className = "term-list hidden";
  ul.innerHTML = '';
};

input.addEventListener("keyup", search, false);





var li = $('li');
var liSelected;
$(window).keydown(function(e) {
  if (e.which === 40) {
    if (liSelected) {
      liSelected.removeClass('selected');
      next = liSelected.next();
      if (next.length > 0) {
        liSelected = next.addClass('selected');
      } else {
        liSelected = li.eq(0).addClass('selected');
      }
    } else {
      liSelected = li.eq(0).addClass('selected');
    }
  } else if (e.which === 38) {
    if (liSelected) {
      liSelected.removeClass('selected');
      next = liSelected.prev();
      if (next.length > 0) {
        liSelected = next.addClass('selected');
      } else {
        liSelected = li.last().addClass('selected');
      }
    } else {
      liSelected = li.last().addClass('selected');
    }
  }
});

.search-field,
.term-list {
  -moz-border-radius: 3px;
  -webkit-border-radius: 3px;
  border-radius: 3px;
}

body {
  text-align: center;
  background: #f2f2f2;
}

.title {
  width: 100%;
  margin: 3em 0 1em;
  text-align: center;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-size: 170%;
  font-weight: 400;
  color: #2a5ba3;
  text-shadow: #fff 1px 1px 0px, #ddd 2px 2px, #ddd 3px 3px 1px;
}

.search-field {
  display: block;
  width: 30%;
  margin: 1em auto 0;
  padding: 0.5em 10px;
  border: 1px solid #999;
  font-size: 130%;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-weight: 400;
  color: #3e8ce0;
}

.term-list {
  list-style: none inside;
  width: 30%;
  margin: 0 auto 2em;
  padding: 5px 10px 0;
  text-align: left;
  color: #777;
  background: #fff;
  border: 1px solid #ddd;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-weight: 400;
}

.term-list li {
  padding: 0.5em 0;
  border-bottom: 1px solid #eee;
}

li.selected {
  background: yellow
}

.term-list strong {
  color: #444;
  font-weight: 700;
}

.hidden {
  display: none;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<h1 class="title">AutoComplete Me</h1>
<input type="text" id="searchBox" class="search-field" autoFocus />
<ul id="searchResults" class="term-list hidden"></ul>

Answer 1

唯一引用 li 的地方是这里

var li = $('li');
var liSelected;
$(window).keydown(function(e) { ...

但那时 dom 中没有添加 li，因此 $('li') 返回零元素。

进一步，

当您从 dom 中删除 li 并在搜索后的每个按键上添加新的 li 时，您将在每次搜索/按键时丢失对 li 标签的引用。

这里，

var clearResults = function() {
 debugger;
  ul.className = "term-list hidden";
  ul.innerHTML = ''; // Removing all li inside the ul
}

因此，您的旧 li 变量正在引用现已删除的旧陈旧 li。

解决方法:

在 appendResults 函数中添加新的 li 后，您需要更新 li 变量。

var appendResults = function() {
  clearResults();
  for (var i = 0; i < sortedResults.length && i < 5; i++) {
    var _li = document.createElement("li"),
      result = prefix +
      sortedResults[i].toLowerCase().replace(terms, '<strong>'+ terms + '</strong>');

    _li.innerHTML = result;

    ul.appendChild(_li);
  }

  li = $('li');
  liSelected = li.filter('.selected');
  $('li').click(function(e) {
    $('input').val($(this).text());
  });
  if (ul.className !== "term-list") {
    ul.className = "term-list";
  }
};

此外，您的搜索功能也会在每次按下和向上键时被调用，您必须检查向上和向下键并返回。

var search = function(e) {
  if(e.which==40||e.which==38) return;
  debugger;
  inputTerms = input.value.toLowerCase();
  results = [];
  termsArray = inputTerms.split(' ');
  prefix = termsArray.length === 1 ? '' : termsArray.slice(0, -1).join(' ') + ' ';
  terms = termsArray[termsArray.length - 1].toLowerCase();

  for (var i = 0; i < searchIndex.length; i++) {
    var a = searchIndex[i].toLowerCase(),
      t = a.indexOf(terms);

    if (t > -1) {
      results.push(a);
    }
  }

  evaluateResults();
};

片段

var searchIndex = ["404 Error", "Address Bar", "Ajax", "Apache", "Autoresponder", "BitTorrent", "Blog", "Bookmark", "Bot", "Broadband", "Captcha", "Certificate", "Client", "Cloud", "Cloud Computing", "CMS", "Cookie", "CSS", "Cyberspace", "Denial of Service", "DHCP", "Dial-up", "DNS Record", "Domain Name", "Download", "E-mail", "Facebook", "FiOS", "Firewall", "FTP", "Gateway", "Google", "Google Drive", "Gopher", "Hashtag", "Hit", "Home Page", "HTML", "HTTP", "HTTPS", "Hyperlink", "Hypertext", "ICANN", "Inbox", "Internet", "InterNIC", "IP", "IP Address", "IPv4", "IPv6", "IRC", "iSCSI", "ISDN", "ISP", "JavaScript", "jQuery", "Meta Search Engine", "Meta Tag", "Minisite", "Mirror", "Name Server", "Packet", "Page View", "Payload", "Phishing", "POP3", "Protocol", "Scraping", "Search Engine", "Social Networking", "Socket", "Spam", "Spider", "Spoofing", "SSH", "SSL", "Static Website", "Twitter", "XHTML"];

var input = document.getElementById("searchBox"),
  ul = document.getElementById("searchResults"),
  inputTerms, termsArray, prefix, terms, results, sortedResults;


var search = function(e) {
  if(e.which==40||e.which==38) return;
  inputTerms = input.value.toLowerCase();
  results = [];
  termsArray = inputTerms.split(' ');
  prefix = termsArray.length === 1 ? '' : termsArray.slice(0, -1).join(' ') + ' ';
  terms = termsArray[termsArray.length - 1].toLowerCase();

  for (var i = 0; i < searchIndex.length; i++) {
    var a = searchIndex[i].toLowerCase(),
      t = a.indexOf(terms);

    if (t > -1) {
      results.push(a);
    }
  }

  evaluateResults();
};

var evaluateResults = function() {
  if (results.length > 0 && inputTerms.length > 0 && terms.length !== 0) {
    sortedResults = results.sort(sortResults);
    appendResults();
  } else if (inputTerms.length > 0 && terms.length !== 0) {
    ul.innerHTML = '<li>Whoah! <strong>' +
      inputTerms +
      '</strong> is not in the index. <br><small><a href="http://google.com/search?q=' +
      encodeURIComponent(inputTerms) + '">Try Google?</a></small></li>';

  } else if (inputTerms.length !== 0 && terms.length === 0) {
    return;
  } else {
    clearResults();
  }
};

var sortResults = function(a, b) {
  if (a.indexOf(terms) < b.indexOf(terms)) return -1;
  if (a.indexOf(terms) > b.indexOf(terms)) return 1;
  return 0;
}

var appendResults = function() {
  clearResults();
 debugger;
  for (var i = 0; i < sortedResults.length && i < 5; i++) {
    var _li = document.createElement("li"),
      result = prefix +
      sortedResults[i].toLowerCase().replace(terms, '<strong>'+ terms + '</strong>');

    _li.innerHTML = result;

    ul.appendChild(_li);
  }
  
  li = $('li');  // Update here
  liSelected = li.filter('.selected'); // Update here
  
  $('li').click(function(e) {
    $('input').val($(this).text());
  });
  if (ul.className !== "term-list") {
    ul.className = "term-list";
  }
};

var clearResults = function() {
  ul.className = "term-list hidden";
  ul.innerHTML = '';
};

input.addEventListener("keyup", search, false);





var li = $('li');
var liSelected;
$(window).keydown(function(e) {
  if (e.which === 40) {
    if (liSelected) {
      liSelected.removeClass('selected');
      next = liSelected.next();
      if (next.length > 0) {
        liSelected = next.addClass('selected');
      } else {
        liSelected = li.eq(0).addClass('selected');
      }
    } else {
      liSelected = li.eq(0).addClass('selected');
    }
    liSelected.trigger('click');
  } else if (e.which === 38) {
    if (liSelected) {
      liSelected.removeClass('selected');
      next = liSelected.prev();
      if (next.length > 0) {
        liSelected = next.addClass('selected');
      } else {
        liSelected = li.last().addClass('selected');
      }
    } else {
      liSelected = li.last().addClass('selected');
    }
    liSelected.trigger('click');
  }
  
});

.search-field,
.term-list {
  -moz-border-radius: 3px;
  -webkit-border-radius: 3px;
  border-radius: 3px;
}

body {
  text-align: center;
  background: #f2f2f2;
}

.title {
  width: 100%;
  margin: 3em 0 1em;
  text-align: center;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-size: 170%;
  font-weight: 400;
  color: #2a5ba3;
  text-shadow: #fff 1px 1px 0px, #ddd 2px 2px, #ddd 3px 3px 1px;
}

.search-field {
  display: block;
  width: 30%;
  margin: 1em auto 0;
  padding: 0.5em 10px;
  border: 1px solid #999;
  font-size: 130%;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-weight: 400;
  color: #3e8ce0;
}

.term-list {
  list-style: none inside;
  width: 30%;
  margin: 0 auto 2em;
  padding: 5px 10px 0;
  text-align: left;
  color: #777;
  background: #fff;
  border: 1px solid #ddd;
  font-family: "Arvo", "Helvetica Neue", Helvetica, arial, sans-serif;
  font-weight: 400;
}

.term-list li {
  padding: 0.5em 0;
  border-bottom: 1px solid #eee;
}

li.selected {
  background: yellow
}

.term-list strong {
  color: #444;
  font-weight: 700;
}

.hidden {
  display: none;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<h1 class="title">AutoComplete Me</h1>
<input type="text" id="searchBox" class="search-field" autoFocus />
<ul id="searchResults" class="term-list hidden"></ul>