function check_email(email) {
	var filter = /^[a-z0-9\._-]+@([a-z0-9_-]+\.)+[a-z]{2,6}$/i;
        if (!filter.test(email)) return false;
        return true;
}

function get_value(text) {

        if ((text==undefined) || (text==null)) return null;
        val = text.value;
	if ((val==undefined) || (val==null) || (val=="")) return null;
	return val;
}


function validate_tell(form) {
	try {
		message = get_value(form.message);
		if ((message==null) || (message=="") || (message.length>140)) {
			alert("The message cannot be empty or longer than 140 characters");
			return false;
		}
		return true;
 	}
	catch(err) {
		alert(err);
		return false;
	}
}

function validate_register_web(form) {	

	try {
        pwd1 = get_value(form.password);
        pwd2 = get_value(form.password2);
        username = get_value(form.username);
        email = get_value(form.email);
	
	var re = /^[A-Za-z0-9]+$/;

        if ((username==null) || (username.length<5) || (username.length>20) || (re.test(username)==false)) {
                alert("Username must be between 5 and 20 characters long and alphanumeric ");
                return false;
        }


        if ((pwd1==null) || (pwd2==null) || (pwd1.length<5) || (pwd2.length<5) || (pwd1.length>20) || (pwd2.length>20)) {
                alert("Passwords must be between 5 and 20 characters long");
                return false;
        }

        if (pwd1!=pwd2) {
                alert("Passwords do not match");
                return false;
        }


        if ((pwd1==null) || (pwd1.length<5) || (pwd1.length>20) || (re.test(pwd1)==false)) {
                alert("Password must be between 5 and 20 characters long and alphanumeric ");
                return false;
        }

        if (!check_email(email)) {
		alert("Valid email is required!");
		return false;
	}

        facebook = get_value(form.facebook_user);
        twitter = get_value(form.twitter_user);

        
        if ((facebook==null) && (twitter==null)) {
        	alert("Your social network is not defined!\nPlease use Twitter and/or Facebook Connect");
       		return false;
	 }

        return true;
	}
	catch(err) {
		alert(err);
		return false;
	}

}