Валидация E-mail в форме регистрации, во время ввода пользователем

{if $cfg.is_on}
    {if $cfg.reg_type == 'invite' && !$correct_invite}
        <p style="margin-bottom:15px; font-size: 14px">{$LANG.INVITES_ONLY}</p>
        {if $msg}<p style="color:red;margin-bottom: 10px">{$msg}</p>{/if}
        <form id="regform" name="regform" method="post" action="/registration">
        <table cellpadding="0" cellspacing="0" border="0">
            <tr>
                <td><strong>{$LANG.INVITE_CODE}:</strong></td>
                <td style="padding-left:15px">
                    <input type="text" name="invite_code" class="text-input" value="" style="width:270px"/>
                </td>
                <td style="padding-left:5px">
                    <input type="submit" name="show_invite" value="{$LANG.SHOW_INVITE}" />
                </td>
            </tr>
        </table>
        </form>
    {else}

{literal}
<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>
{/literal}

<input id="validate" name="email" type="text" class="text-input" size="30" value="{$email}"/>
                        <span class="regstar">*</span>

<input id="validate" name="email" type="text" class="text-input" size="30" value="{$email}"/>
                        <span class="regstar">*</span><span id="validEmail"></span>