Javascript email check function

isEmail.js

function isEmail(email) {
	var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
	if(reg.test(email) == false) {
		return false;
	}
	else
	{
		return true;   
	}
}