function validateEmail(field, alertText)
{
    var emailRegExp = /^[A-Za-z0-9._\-]+@[A-Za-z0-9]([A-Za-z0-9._\-]*\.)+[A-Za-z]+$/;
    if (!emailRegExp.test(field.value)){
		alert(alertText);
		field.focus();
		return false;
    } else
        return true;
}

function chk(f)
{
 	if      (!validateEmail(f.mail_to, 'Niepoprawny adres e-mail.')) return false;
 	else if (!validateEmail(f.mail_from, 'Niepoprawny adres e-mail.')) return false;
	else return true;
}
function okno_no_scroll(url, width, height) {
        width1=width/2;
		height1=height/2;
		x=screen.availWidth/2-width1;
		y=screen.availHeight/2-height1;
		var Win = window.open(url,"displayWindow",'width=' + width + ',height=' + height + ',resizable=0, scrollbars=0, menubar=no,status=1, left='+x+', top='+y );
		Win.focus();
};

function czysc(pole)
{
	document.getElementById(pole).value='';
}