另一个简单而完整的选择:

<input type="text" id="Email"/>
<div id="ClasSpan"></div>   
<input id="ValidMail" type="submit"  value="Valid"/>  


function IsEmail(email) {
    var regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;
    return regex.test(email);
}

$("#ValidMail").click(function () {
    $('span', '#ClasSpan').empty().remove();
    if (IsEmail($("#Email").val())) {
        //aqui mi sentencia        
    }
    else {
        $('#ClasSpan').append('<span>Please enter a valid email</span>');
        $('#Email').keypress(function () {
            $('span', '#itemspan').empty().remove();
        });
    }
});

if($("input#email-address").getVerimailStatus() < 0) { 

(incorrect code)

}

if($("input#email-address").getVerimailStatus() == 'error') { 

(right code)

}

<script type="text/javascript">
    $(document).ready(function() {
      $('.form_error').hide();
      $('#submit').click(function(){
           var name = $('#name').val();
           var email = $('#email').val();
           var phone = $('#phone').val();
           var message = $('#message').val();
           if(name== ''){
              $('#name').next().show();
              return false;
            }
            if(email== ''){
               $('#email').next().show();
               return false;
            }
            if(IsEmail(email)==false){
                $('#invalid_email').show();
                return false;
            }

            if(phone== ''){
                $('#phone').next().show();
                return false;
            }
            if(message== ''){
                $('#message').next().show();
                return false;
            }
            //ajax call php page
            $.post("send.php", $("#contactform").serialize(),  function(response) {
            $('#contactform').fadeOut('slow',function(){
                $('#success').html(response);
                $('#success').fadeIn('slow');
               });
             });
             return false;
          });
      });
      function IsEmail(email) {
        var regex = /^([a-zA-Z0-9_\.\-\+])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
        if(!regex.test(email)) {
           return false;
        }else{
           return true;
        }
      }
  </script>

<form action="" method="post" id="contactform">
                            <table class="contact-table">
                              <tr>
                                <td><label for="name">Name :</label></td>
                                <td class="name"> <input name="name" id="name" type="text" placeholder="Please enter your name" class="contact-input"><span class="form_error">Please enter your name</span></td>
                              </tr>
                              <tr>
                                <td><label for="email">Email :</label></td>
                                <td class="email"><input name="email" id="email" type="text" placeholder="Please enter your email" class="contact-input"><span class="form_error">Please enter your email</span>
                                  <span class="form_error" id="invalid_email">This email is not valid</span></td>
                              </tr>
                              <tr>
                                <td><label for="phone">Phone :</label></td>
                                <td class="phone"><input name="phone" id="phone" type="text" placeholder="Please enter your phone" class="contact-input"><span class="form_error">Please enter your phone</span></td>
                              </tr>
                              <tr>
                                <td><label for="message">Message :</label></td>
                                <td class="message"><textarea name="message" id="message" class="contact-input"></textarea><span class="form_error">Please enter your message</span></td>
                              </tr>
                              <tr>
                                <td></td>
                                <td>
                                  <input type="submit" class="contactform-buttons" id="submit"value="Send" />
                                  <input type="reset" class="contactform-buttons" id="" value="Clear" />
                                </td>
                              </tr>
                            </table>
     </form>
     <div id="success" style="color:red;"></div>

你可以使用常规的旧javascript:

function isEmail(email) {
  var regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;
  return regex.test(email);
}

<!-- Dont forget to include the jQuery library here -->
<script type="text/javascript" src="jquery-1.3.2.min.js"></script>
<script type="text/javascript">

$(document).ready(function() {

    $("#validate").keyup(function(){

        var email = $("#validate").val();

        if(email != 0)
        {
            if(isValidEmailAddress(email))
            {
                $("#validEmail").css({
                    "background-image": "url('validYes.png')"
                });
            } else {
                $("#validEmail").css({
                    "background-image": "url('validNo.png')"
                });
            }
        } else {
            $("#validEmail").css({
                "background-image": "none"
            });         
        }

    });

});

function isValidEmailAddress(emailAddress) {
    var pattern = new RegExp(/^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i);
    return pattern.test(emailAddress);
}

</script>

<style>
    #validEmail
    {
        margin-top: 4px;
        margin-left: 9px;
        position: absolute;
        width: 16px;
        height: 16px;
    }

    .text
    {
        font-family: Arial, Tahoma, Helvetica;
    }
</style>

    <title>Live Email Validation with jQuery Demo</title>
</head>
<body>
    <div class="text"><h1>Reynoldsftw.com - Live Email Validation</h1><h2>Type in an email address in the box below:</h2></div>
    <div><input type="text" id="validate" width="30"><span id="validEmail"></span></div>
    <div class="text"><P>More script and css style

: www.htmldrive.net

来源:htmldrive.com

http://so.devilmaycode.it/jquery-validate-e-mail-address-regex/ 使用新的正则表达式 增加了对地址标签(+号)的支持

function isValidEmailAddress(emailAddress) { var pattern = /^([a-z\d!#$%&'*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+(\.[a-z\d!#$%&'*+\-\/=?^_`{|}~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]+)*|"((([ \t]*\r\n)?[ \t]+)?([\x01-\x08\x0b\x0c\x0e-\x1f\x7f\x21\x23-\x5b\x5d-\x7e\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|\\[\x01-\x09\x0b\x0c\x0d-\x7f\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))*(([ \t]*\r\n)?[ \t]+)?")@(([a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\d\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.)+([a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]|[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF][a-z\d\-._~\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]*[a-z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])\.?$/i; return pattern.test(emailAddress); };

if( !isValidEmailAddress( emailaddress ) ) { /* do stuff here (email is invalid) */ }

这是由用户Luca Filosofi提供的答案