Autocomplete 自动完成
功能：输入框在输入关键字后，根据输入的内容给出相关的下拉框供用户选择，自动完成输入内容。
插件：使用jqueryUI的自动完成小部件，文档地址：https://jqueryui.com/autocomplete/
API：文档链接：https://api.jqueryui.com/autocomplete/#option-source
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>jQuery UI Autocomplete - Default functionality</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<link rel="stylesheet" href="/resources/demos/style.css">
<script src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script>
$( function() {
var availableTags = [
"ActionScript",
"AppleScript",
"Asp",
"BASIC",
"C",
"C++",
"Clojure",
"COBOL",
"ColdFusion",
"Erlang",
"Fortran",
"Groovy",
"Haskell",
"Java",
"JavaScript",
"Lisp",
"Perl",
"PHP",
"Python",
"Ruby",
"Scala",
"Scheme"
];
$( "#tags" ).autocomplete({
source: availableTags
});
} );
</script>
</head>
<body>
<div class="ui-widget">
<label for="tags">Tags: </label>
<input id="tags">
</div>
</body>
</html>