function FormValidation_LogIn() {
	var theForm = document.login;
	
	if (trimWhitespace(theForm.username.value) == '') {
		alert("Username is required.");
		return false;
	}
	else if (!isAlphanumeric(theForm.username.value)) {
		alert("Username only accepts alphanumeric characters.");
		return false;
	}
	else if (trimWhitespace(theForm.username.value).length < 5 || trimWhitespace(theForm.username.value).length > 20) {
		alert("Username only accepts 5 to 20 of characters.");
		return false;
	}
	else if (trimWhitespace(theForm.password.value) == '') {
		alert("Password is required.");
		return false;
	}
	else if (trimWhitespace(theForm.password.value).length < 5 || trimWhitespace(theForm.password.value).length > 20) {
		alert("Password only accepts 5 to 20 of characters.");
		return false;
	}
	else {
		return true;
	}
}