abstract：老師我有問題：1.下面圖片的undefine在谷歌瀏覽器在哪查看？ 2.console.log(Math.rand
老師我有問題：1.下面圖片的undefine在谷歌瀏覽器在哪查看？
2.console.log(Math.random()+1,10) 后面的10代表啥？
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>實(shí)戰(zhàn)聊天框信息</title>
<link rel="stylesheet" href="../common/css/admin.css">
</head>
<body>
<div class="box">
<h2>在線客服</h2>
<div class="content">
<ul>
</ul>
</div>
<div class="retext">
<textarea name="text" id="text" cols="40" rows="5"></textarea>
<button name="send" type="button">發(fā)送</button>
</div>
</div>
<script>
let txt = document.getElementsByName('text').item(0);
let btn = document.getElementsByName('send').item(0);
let ul = document.getElementsByTagName('ul').item(0);
document.onkeydown = function(event){
var e = event || window.event;
if(e && e.keyCode == 13){//13 為enter鍵
chatword();
}
}
btn.onclick = chatword;
function chatword(){
if(txt.value == null){
alert('輸入內(nèi)容為空');
}
let num = 0;//計(jì)數(shù)器，num>10,清屏
console.log(txt.value);
let show = document.createElement('li');
show.innerHTML = '<a href=""><img src="images/send.jpg" alt="chat">' + txt.value + '</a>';
ul.appendChild(show);
num++;
setTimeout(function(){
let arr = ['來了，老弟!','只要你乖給你買條街！','食屎啦你','怎么肥事?','小老弟','火星情報(bào)局','楊迪','薛之謙'];
let reply = document.createElement('li');
reply.innerHTML = '<a href=""><img src="images/reply.jpg" alt="chat">' + arr[Math.round(Math.random()*7)] + '</a>';
ul.appendChild(reply);
num++;
if(num>10){
ul.innerHTML = '';//清空
}
},1200);
}
</script>
</body>
</html>
Correcting teacher：天蓬老師Correction time：2018-12-17 11:26:32
Teacher's summary：cosole.log()中的字面量會(huì)原樣輸出, 它的意義 , 讓你自己指定