上效果：
主要思路:
函数indexOf() 、join()、innerHTML的使用，还有 用完的数组要清空
1 <!DOCTYPE html> 2 <html> 3 <head lang="en"> 4 <meta charset="UTF-8"> 5 <title></title> 6 <style> 7 * { 8 margin: 0; 9 padding: 0; 10 } 11 body { 12 font-size: 20px; 13 } 14 .box { 15 600px; 16 height: 40px; 17 margin: 200px auto; 18 position: relative; 19 } 20 #txt { 21 488px; 22 height: 38px; 23 border: 1px solid #3385ff; 24 font-size: 20px; 25 float: left; 26 outline: none; 27 padding-left: 10px; 28 } 29 #search { 30 100px; 31 height: 40px; 32 float: left; 33 border:0 none; 34 background-color: #3385ff; 35 color:#fff; 36 cursor: pointer; 37 } 38 #keywords { 39 position: absolute; 40 top: 40px; 41 left: 0; 42 background-color: rgb(12, 255, 24); 43 list-style: none; 44 500px;; 45 } 46 li { 47 line-height: 24px; 48 } 49 </style> 50 </head> 51 <body> 52 <div class="box"> 53 <div class="baidu"> 54 <input type="text" id="txt"/> 55 <input type="button" value="百度一下" id="search"/> 56 </div> 57 <ul id="keywords"></ul> 58 </div> 59 <script> 60 61 // 这里是模拟我们的数据库 62 var keywords = ["冬天吃什么","冬天的离别","冬天有多冷","林丹林丹","林丹夺冠","123","123456","JavaScript","Java","黄鳝","黄鳝煮汤","黄鳝煮粥","咸鱼","咸鱼茄子煲","咸鱼翻身","十九大","十八大","十全十美"]; 63 var txt = document.getElementById('txt'); 64 var search = document.getElementById('search'); 65 var ul = document.getElementById('keywords'); 66 67 txt.onkeyup = function () { 68 // 取出目前输入的关键字 69 var txtValue = txt.value.trim(); 70 71 //存储与当前关键字相关的字符串信息的数组 72 var aimArr = []; 73 for(var i = 0 ; i < keywords.length ; i++ ) { 74 // keywords数组中的字符串是否含义该关键字，含有的话存储进aimArr 75 if(keywords[i].indexOf(txtValue) != -1) { // 没有返回-1 76 aimArr.push(keywords[i]); 77 } 78 } 79 // 如果输入为空 80 if (txtValue.length == 0 ) { 81 aimArr = []; 82 } 83 84 // 把aimArr设置进ul中js动态添加的li里面 85 // 创建li 86 var lis = []; // 新创建的li存储在lis数组里面 87 for(var i = 0 ; i < aimArr.length ; i++ ) { 88 lis.push("<li>"+aimArr[i]+"</li>"); 89 } 90 // 把lis数组转为字符串，添加进ul中 91 ul.innerHTML = lis.join(""); 92 93 } 94 95 96 97 </script> 98 </body> 99 </html>