app直播源码，点击搜索栏自动弹出下拉框

<!DOCTYPE html><br><html><br><head><br>    <meta charset="UTF-8"><br>    <meta http-equiv="X-UA-Compatible" content="IE=edge"><br>    <meta name="viewport" content="width=<br>    , initial-scale=1.0"><br>    <title>Document</title><br></head><br><body><br>    搜索：<input type="text"><br><br>    <ul><br>    </ul><br></body><br></html><br><script><br>    let oInput=document.querySelector('input');<br>    let oUl=document.querySelector('ul');<br>    oInput.oninput=function (){<br>        if(this.value != ""){<br>            let xhr=new XMLHttpRequest();<br>        xhr.open('GET','sousuo.php?wd='+this.value,true);<br>        xhr.send();<br>        xhr.onreadystatechange=function (){<br>            if(xhr.readyState==4 && xhr.status==200){<br>                fun(xhr.responseText);<br>                console.log(xhr.responseText);<br>            }<br>        }<br>        }else{<br>oUl.innerHTML = "";<br>}<br>        <br>    }<br>    function fun(resText){<br>        //拼接<br>        let strHtml='';<br>        //将JSON形式的字符串转为数组<br>        let obj=JSON.parse(resText);<br>        for(let index in obj){<br>strHtml += `<li>${obj[index]}</li>`;<br>}<br>oUl.innerHTML = strHtml;<br>}<br></script>