function DecToHex(dec) {
	dec = Math.abs(dec);
	var hex = "";
	var a = "" + dec;
	a = a.length;
	var h = "0123456789ABCDEF";
	for (n=0; n<a; n++){
		he = h.charAt(dec-Math.floor(dec/16)*16);
		dec = (dec - h.indexOf(he)) / 16;
		hex = he + hex;
	}
	if (hex.charAt(0) == "0") hex = hex.substring(1,hex.length);
	if (hex.length == 1) hex = "0" + hex;
	return hex;
}

function hgrad(sirka) {

	document.write("<table cellspacing=0 width=\"100%\"><tr height=\"" + sirka + "\">");
	for (i=255; i>=0;i=i-1) {
		document.write("<td bgcolor=\"#" + DecToHex(i) + "" + DecToHex(i) + "" + DecToHex(i) + "\"></td>");
	    	}
	document.write("</tr></table>");

}