function ValidateSignUp()
{
   
    element = document.getElementById('txtEmailNewsletter');
    if (element.value == "")      
    {
                alert('Please enter your email');
                element.focus();
                return;
    }
    if (ValidateEmailNewsLetter(element.value))
    {
       var result= AjaxNewsLetter.SubmitNewsLetter(element.value);
       
       if (result!= null && result.error==null && result.value!=null){
             alert(result.value);
             element.value="";
       }
       
	   else  alert('It happened an error, Please to communicate the administrator');
    }
    
}


function ValidateEmailNewsLetter(incoming) 
{
    var emailstring = incoming;
    var ampIndex = emailstring.indexOf("@");
    var afterAmp = emailstring.substring((ampIndex + 1), emailstring.length);
    // find a dot in the portion of the string after the ampersand only
    var dotIndex = afterAmp.indexOf(".");
    // determine dot position in entire string (not just after amp portion)
    dotIndex = dotIndex + ampIndex + 1;
    // afterAmp will be portion of string from ampersand to dot
    afterAmp = emailstring.substring((ampIndex + 1), dotIndex);
    // afterDot will be portion of string from dot to end of string
    var afterDot = emailstring.substring((dotIndex + 1), emailstring.length);
    var beforeAmp = emailstring.substring(0,(ampIndex));
    var email_regex = /^\w(?:\w|-|\.(?!\.|@))*@\w(?:\w|-|\.(?!\.))*\.\w{2,3}/ 
    // index of -1 means "not found"
    if ((emailstring.indexOf("@") != "-1") &&
	    (emailstring.length > 5) &&
	    (afterAmp.length > 0) &&
	    (beforeAmp.length > 1) &&
	    (afterDot.length > 1) &&
	    (email_regex.test(emailstring)) ) 
    {
	    return true;
    } 
    else {
	    alert("Please check your email address");
	    return false;
    }
    
}