function checkMail(mail)
{
	var x = mail;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) return 1
	else return 0;
}

function send() {
	
	mail_subject = document.getElementById('f_subject').value;
	mail_text = document.getElementById('f_text').value;
	mail_mail = document.getElementById('f_mail').value;
	
	if ( (mail_text == '') || (checkMail(mail_mail) == 0)) {
		alert("Prosim vyplňte formulář korektním emailem.\nPoložka dotaz nesmí byt prázdna");
		return false;
	} else {
	    document.getElementById('send_bt').innerHTML = "<img src='images/loader.gif' style=\"margin-top:2px;\">&nbsp;Odesilam dotaz";
		xmlSend('send_mail.php?from='+mail_mail+'&subject='+mail_subject+'&text='+mail_text);    
	}

	return true;	
}

function xmlSend(req1) {
		var xmlHttpReq = false;
		var self = this;
		// Mozilla/Safari
		if (window.XMLHttpRequest) {  self.xmlHttpReq = new XMLHttpRequest();  }
	    // IE
    	else if (window.ActiveXObject) {   self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");    }

    self.xmlHttpReq.open('GET', req1, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.onreadystatechange = function() {
        if (self.xmlHttpReq.readyState == 4) {
            updateEmail(self.xmlHttpReq.responseText);
        }
    }
    
    self.xmlHttpReq.send(req1);
}

function updateEmail(str) {
	    document.getElementById('send_bt').innerHTML = str;
}