<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.bg {
background-color: yellow;
}
</style>
</head>
<body>
<input type="text" id="txtUserName"> <br>
<input type="password" id="txtUserPassword"> <br>
<input type="button" value=" 登 录 " id="btnLogin">
<script>
// 检测用户名是否是3-6位，密码是否是6-8位，如果不满足要求高亮显示文本框
var btnLogin = document.getElementById('btnLogin');
btnLogin.onclick = function () {
// 检测用户名是否是3-6位，密码是否是6-8位
var txtUserName = document.getElementById('txtUserName');
var txtUserPassword = document.getElementById('txtUserPassword');
//检测用户名是否是3-6位
if (txtUserName.value.length < 3 || txtUserName.value.length > 6) {
txtUserName.className = 'bg';
return;
} else {
txtUserName.className = '';
}
// 密码是否是6-8位
if (txtUserPassword.value.length < 6 || txtUserPassword.value.length > 8) {
txtUserPassword.className = 'bg';
return;
} else {
txtUserPassword.className = '';
}
//
console.log('执行登录');
}
</script>
</body>
</html>
