function checkMail()
{
	var x = document.forms["form1"].email.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) return true;
	else return false;
}

function check_items()
{   var dwg=false;

    if(check_items.arguments[0]=="dwg") {

       dwg=(document.forms["form1"].adresa.value=="");
    };
	if(checkMail()&&(document.forms["form1"].dotaz.value!="")&&(document.forms["form1"].osoba.value!="")&&(document.forms["form1"].telefon.value!="")&&(document.forms["form1"].adresa.value!="")&&!dwg){
		if (odesilam==true) alert("Your message is being sent!");
		else document.form1.submit();
		odesilam=true;
		 	return true;
	}
	else {
		alert("Please fill in boldly labeled fields!");
			return false;
	}
}