console
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Homework of First week</title>
<link rel="stylesheet" href="style.css">
<style>
ol li{background:black;color:white;}
input.add {front-weight:bold;}
#add
{
text-align:center;
font-weight:bold;
}
</style>
<script>
function addcity(){
var obj_lis = document.getElementById("o").getElementsByTagName("li");
console.log(obj_lis);
var text1 = document.getElementById("city").value;
var ol = document.getElementById("o");
var li = document.createElement("li");
if (text1 != '')
{
li.innerHTML = text1;
ol.appendChild(li);
}
}
</script>
</head>
<body>
<h3>中国的城市名</h3>
<ol id="o">
<li>上海</li>
<li>北京</li>
<li>广州</li>
</ol>
<input type="text" id="city" placeholder="请输入新的列表项目"/>
<input type="button" id="add" value="添加城市" onClick="addcity()"/>
</body>
</html>