/*
    This function is called when
    the 'Sign Guestbook' button is pressed
    Output : true if all input are correct, false otherwise
*/
function checkForm()
{
    // the variables below are assigned to each
    // form input 
    var gname, gemail,gdicq, gurl, gmessage;
    with(window.document.guestform)
    {
        gname    = txtName;
        gemail   = txtEmail;
	gdicq   = txtEmail;
        gurl     = txtUrl;
        gmessage = mtxMessage;
    }
    
    // if name is empty alert the visitor
    if(trim(gname.value) == '')
    {
        alert('Prosim vlozte sve jmeno');
        gname.focus();
        return false;
    }
    // alert the visitor if email is empty or the format is not correct 
    else if(trim(gemail.value) != '' && !isEmail(trim(gemail.value)))
    {
        alert('Vase emailova adresa neni ve spravnem formatu');
        gemail.focus();
        return false;
    }
    // alert the visitor if message is empty
    else if(trim(gmessage.value) == '')
    {
        alert('Prosim vlozte nejakou zpravu');
        gmessage.focus();
        return false;
    }
    else
    {
        // when all input are correct 
        // return true so the form will submit        
        return true;
    }
}

/*
Strip whitespace from the beginning and end of a string
Input  : a string
Output : the trimmed string
*/
function trim(str)
{
    return str.replace(/^\s+|\s+$/g,'');
}

/*
Check if a string is in valid email format. 
Input  : the string to check
Output : true if the string is a valid email address, false otherwise.
*/
function isEmail(str)
{
    var regex = /^[-_.a-z0-9]+@(([-a-z0-9]+\.)+(ad|ae|aero|af|ag|ai|al|am|an|ao|aq|ar|arpa|as|at|au|aw|az|ba|bb|bd|be|bf|bg|bh|bi|biz|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|com|coop|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|edu|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gh|gi|gl|gm|gn|gov|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|in|info|int|io|iq|ir|is|it|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|mg|mh|mil|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|museum|mv|mw|mx|my|mz|na|name|nc|ne|net|nf|ng|ni|nl|no|np|nr|nt|nu|nz|om|org|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|pro|ps|pt|pw|py|qa|re|ro|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)|(([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5])\.){3}([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]))$/i;
    return regex.test(str);
}



function BBCemoticon(text) {
	var txtarea = document.guestform.mtxMessage;
	text = ''+text+'';
	if (txtarea.createTextRange && txtarea.caretPos) {
		var caretPos = txtarea.caretPos;
		caretPos.text = caretPos.text.charAt(caretPos.text.length - 1) == ' ' ? caretPos.text + text + ' ' : caretPos.text + text;
		txtarea.focus();
	} else {
		txtarea.value  += text;
		txtarea.focus();
	}
	}
	
	// Claret position Code from http://www.faqts.com/knowledge_base/view.phtml/aid/1052/fid/130
function storeCaret(textEl){
	if (textEl.createTextRange) textEl.caretPos = document.selection.createRange().duplicate();
	}
	
function TextVanish(thefield){
	if (thefield.defaultValue==thefield.value)
	thefield.value = ""
}
function zobraz()
{
	obj = document.getElementById('logform')
	if (obj.style.display == 'none')
	{
		obj.style.display = 'block';
	}
	else
		obj.style.display = 'none';
}
function shoh(id) { 
	
	if (document.getElementById) { // DOM3 = IE5, NS6
		if (document.getElementById(id).style.display == "none"){
			document.getElementById(id).style.display = 'block';
		} else {
			document.getElementById(id).style.display = 'none';			
		}	
	} else { 
		if (document.layers) {	
			if (document.id.display == "none"){
				document.id.display = 'block';
			} else {
				document.id.display = 'none';
			}
		} else {
			if (document.all.id.style.visibility == "none"){
				document.all.id.style.display = 'block';
			} else {
				document.all.id.style.display = 'none';
			}
		}
	}
}