// The user has pressed the "advanced search guest" button.
function guestButtonPressed() {
	document.loginForm.login_as_guest.value = 'Y';
	document.loginForm.submit();
}	

// The user has pressed the "quick search guest" button.
function qguestButtonPressed() {
	document.loginForm.login_as_guest.value = 'Q';
	document.loginForm.submit();
}	

// The user has pressed the "login" button.
function loginButtonPressed() {
	document.loginForm.login_as_guest.value = 'N';
	login();
}	

// The user has pressed the "reset" button.
function resetButtonPressed() {
	document.passwordForm.password.value = '';
	document.usernameForm.username.value = '';
	document.usernameForm.username.focus();
}

// The user has pressed "enter" after typing in his/her username.
function usernameFormSubmitted() {
	document.loginForm.login_as_guest.value = 'N';
	document.passwordForm.password.focus();
	return false;
}

// The user has pressed "enter" after typing in his/her password.
function passwordFormSubmitted() {
	document.loginForm.login_as_guest.value = 'N';
	login();
	return false;
}

// Verify username and password fields are not empty then login to EarthExplorer.
function login() {
	if (document.usernameForm.username.value === '' ||
	    document.passwordForm.password.value === '') {

		alert("Please enter a username and password to continue.");
		document.usernameForm.username.focus();
	} else {
		document.loginForm.username.value = document.usernameForm.username.value;
		document.loginForm.password.value = document.passwordForm.password.value;
		document.loginForm.submit();
	}
}