小编Sup*_*adi的帖子

function validate() {
	var username = document.getElementById("username").value;
	var password = document.getElementById("password").value;

	if (username == "") {

		document.getElementById("message").innerHTML = "USERNAME CANNOT BE EMPTY";
		document.getElementById("username").style.borderColor = "red";
		return false;
	}
	if (password == "") {


		document.getElementById("message").innerHTML = "PASSWORD CANNOT BE EMPTY";
		document.getElementById("password").style.borderColor = "red";
		return false;
	}
}

#username:focus {
	background-color: yellow;
	border-color: green;
}

#password:focus {
	background-color: yellow;
	border-color: green;
}

#message {
	color: red;
}

<form onsubmit=" return validate()">
    LOGIN:-
    <br>
    <input id="username" type="text" name="username" placeholder="USERNAME">
    <br>
    <input id="password" type="password" …