Validation of Email using jquery

$(document).ready(function() {
  $('#txtEmail').blur(function() {
      if(validateEmail('txtEmail'))
      {
          alert('Email is valid');
      }
      else
      {
          alert('Invalid Email Address');
      }
   });
});
function validateEmail(txtEmail){
   var a = document.getElementById(txtEmail).value;
   var filter = /^[a-zA-Z0-9._-]+@[a-zA-Z.-]+\.[a-zA-Z]{2,4}$/;
    if(filter.test(a)){
        return true;
    }
    else{
        return false;
    }
}