<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script>
var sName = '李四';
var iAge = '20';
var sSex = '男';
var sResult = sName + sSex;
alert(sResult)
// 字符串和数字进行拼接，底层自动把数字类型转换成字符串，这种操作叫隐式类型转换
sResult = sName + iAge;
alert(sResult);
// +=
iAge += sSex
alert(iAge)
</script>
</head>
<body>
</body>
</html>