function wyslij() {
	var correct = true;
	if(!isEmail(document.forms[0].mail.value)) {
		alert("You must enter correctly your email address\nMusisz prawidłowo wpisać swój adres email");
		correct = false;
	}
	if(document.forms[0].name.value == '' && correct) {
		alert("You must enter your name\nMusisz wpisać swoje imię");
		correct = false;
	}
	if(document.forms[0].subject.value == '' && correct) {
		alert("You must enter topic\nMusisz wpisać temat");
		correct = false;
	}
	if(document.forms[0].content.value == '' && correct) {
		alert("You must write content of mail\nMusisz wpisać treść listu");
		correct = false;
	}
	if(correct) {
		makeRequest("mail.php");
	}
}
function isEmail(str) {
  // are regular expressions supported?
  var supported = 0;
  if (window.RegExp) {
    var tempStr = "a";
    var tempReg = new RegExp(tempStr);
    if (tempReg.test(tempStr)) supported = 1;
  }
  if (!supported) return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
  var r1 = new RegExp("(@.*@)|(\\.\\.)|(@\\.)|(^\\.)");
  var r2 = new RegExp("^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$");
  return (!r1.test(str) && r2.test(str));
}