Simple email validation using JS

function validEmail(e) {

    var filter = /^\s*[\w\-\+_]+(\.[\w\-\+_]+)*\@[\w\-\+_]+\.[\w\-\+_]+(\.[\w\-\+_]+)*\s*$/;
    if(filter.test(e)){alert("valid email")}
  else{alert("invalid email")}

}

this code will throw false for any invalid email address. This code checks validity with respect to what is email pattern and what are permissible characters