help with additional email validation

help with additional email validation

I have a form which uses JQuery to validate fields and PHP to submit to DB. Current validation only looks to see if a field is empty and if it is displays and error msg. I would like to add addtn't functionality to check to see if an email address is invalid and if so displays an invalid email address msg. Need some help doing that please.

Current JS validation looks like this.

$(function() {
  $('label.error').hide();
var email = $("input#email").val();
        if (email == "") {
      $("label#email_error").show();
      $("input#email").focus();
      return false;
    }
});

in the form

<input id="email" name="email"  maxlength="120" type="text" autocomplete="off"/>
<label class="error" for="email" id="email_error">This field is required.</label>

TIA