function enableButtonSignInSubmit() {
	var buttonSignInSubmit = $('sign-in-submit');
	if(buttonSignInSubmit) {
		buttonSignInSubmit.removeProperty('disabled');
	}
}
function disableButtonSignInSubmit() {
	var buttonSignInSubmit = $('sign-in-submit');
	if(buttonSignInSubmit) {
		buttonSignInSubmit.setProperty('disabled', 'disabled');
	}
};
function submitSignIn() {
	if(canSubmitSignIn()) {
		var formSignIn = $('sign-in');
		if(formSignIn) {
			formSignIn.submit();
		}
		return true;
	}
	else {
		return false;
	}
};
function canSubmitSignIn() {
	if(typeof canSubmitSignInCustom == 'function') {
		return canSubmitSignInCustom();
	}
	else {
		return isEmail('login-email', 'Please specify a valid email address.');
	}
};
window.addEvent('domready', function() {
	var buttonSignInSubmit = $('sign-in-submit');
	if(buttonSignInSubmit) {
		buttonSignInSubmit.addEvent('click', function(event) {
			event.stop();
			disableButtonSignInSubmit();
			if(!submitSignIn()) {
				enableButtonSignInSubmit();
			}
		});
	}
	var formSignIn = $('sign-in');
	if(formSignIn) {
		formSignIn.addEvent('submit', function(event) {
			event.stop();
			submitSignIn();
		});
	}
});