function _recalc() {
var vyska
if (document.forms.bmi.vyska.value == 0){
	alert("Výška nesmí být nula!");
}
else
{
		vyska = (document.forms.bmi.vyska.value.indexOf(',') != 1 )? (parseFloat(document.forms.bmi.vyska.value.replace(",","."))):(parseFloat(document.forms.bmi.vyska.value));
		vyska = vyska / 100;
		vaha = (document.forms.bmi.vaha.value.indexOf(',') != 1 )? (parseFloat(document.forms.bmi.vaha.value.replace(",","."))):(parseFloat(document.forms.bmi.vaha.value));
		_index = Math.round(100 * (vaha / (vyska*vyska))) / 100 ;				

		if (isNaN(vyska) || isNaN(vaha)) {
				alert("Zadejte čísla");		
				return;
		}

		document.forms.bmi.bmi.value = _index;
		
		if (_index <= 20){
			document.forms.bmi.kategorie.value="podváha";
		}
		if (_index  > 20 && _index <= 25){
			document.forms.bmi.kategorie.value="norma";
		}
		if (_index  > 25 && _index <= 30){
			document.forms.bmi.kategorie.value="nadváha";
		}
		if (_index  > 30 &&  _index <= 40){
			document.forms.bmi.kategorie.value="obezita";
		}
		if (_index  >= 40){
			document.forms.bmi.kategorie.value="těžká obezita";
		}
}
}

function getElementsByClassName(oClassNames, strTagName, oElm){
    if (oElm == null)
        oElm = document;
    if (strTagName == null)
        strTagName = '*';
    var arrElements = (strTagName == "*" && oElm.all)? oElm.all : oElm.getElementsByTagName(strTagName);
  
    var arrReturnElements = new Array();
    var arrRegExpClassNames = new Array();
    if(typeof oClassNames == "object"){
        for(var i = 0; i < oClassNames.length; i++){
            arrRegExpClassNames.push(new RegExp("(^|\\s)" + oClassNames[i].replace(/\-/g, "\\-") + "(\\s|$)"));
        }
    }
    else{
        arrRegExpClassNames.push(new RegExp("(^|\\s)" + oClassNames.replace(/\-/g, "\\-") + "(\\s|$)"));
    }
    var oElement;
    var bMatchesAll;
    for (var j = 0; j < arrElements.length; j++){
        oElement = arrElements[j];
        bMatchesAll = true;
        for(var k = 0; k < arrRegExpClassNames.length; k++){
            if(!arrRegExpClassNames[k].test(oElement.className)){
                bMatchesAll = false;
                break;                      
            }
        }
        if (bMatchesAll){
            arrReturnElements.push(oElement);
        }
    }
    return (arrReturnElements)
}
// pro ie5 nutno pridat podporu metody push pro pole
if(typeof Array.prototype.push != "function"){
    Array.prototype.push = ArrayPush;
    function ArrayPush(value){
        this[this.length] = value;
    }
}

function handleInputClicked(inputObj, hideInputFakeText) {
	if(hideInputFakeText)
		inputObj.style.backgroundImage = 'none';
}

try {
	document.execCommand("BackgroundImageCache", false, true);
} catch(err) {}