/**
* @file hypokalkulacka.js
* @inspired by http://www.reality.sk/
* @author Ing. Rene Chrenko
* @site  http://www.itstudio.sk
* @date 16. 10, 2008
*/
function rref (elstringid) {
		if (document.all) return document.all[elstringid]; 
		else
		if (document.getElementById) return document.getElementById(elstringid);
	}

	function poc() {
		if (rref("doba").value <= 0)
			rref("doba").value='0';
		rref("splatka").value=Math.round(((rref("uver_h").value*(rref("urok_h").value/1200))/(1-(Math.pow((1/(1+(rref("urok_h").value/1200))),(rref("doba").value*12))))));
		if (isNaN(rref("splatka").value))
			rref("splatka").value='0';
	}
	function zup() {
		if (rref("uver").value <= 0)
			rref("uver").value='0';
		var str;
		str = rref("uver").value;
		rref("uver_h").value = str.replace(",",".");
		rref("splatka").value=Math.round(((rref("uver_h").value*(rref("urok_h").value/1200))/(1-(Math.pow((1/(1+(rref("urok_h").value/1200))),(rref("doba").value*12))))));
		if (isNaN(rref("splatka").value))
			rref("splatka").value='0';
	}
	function prep() {
		if (rref("urok").value <= 0)
			rref("urok").value='0';
		var str;
		str = rref("urok").value;
		rref("urok_h").value = str.replace(",","."); 
		rref("splatka").value=Math.round(((rref("uver_h").value*(rref("urok_h").value/1200))/(1-(Math.pow((1/(1+(rref("urok_h").value/1200))),(rref("doba").value*12))))));
		if (isNaN(rref("splatka").value))
			rref("splatka").value='0';
	}