function init_calc(){
	var inp=document.forms.calc.getElementsByTagName("input");
	for(var i=0; i<inp.length; i++)
		inp[i].onchange=inp[i].onclick=function(){calc_form()};
	calc_form();
};


function calc_form(){
	var sum=0;
	var inp=document.forms.calc.getElementsByTagName("input");
	for(var i=0; i<inp.length; i++){
		if((inp[i].className=="chb" || inp[i].className=="rad") && inp[i].checked){
			if(inp[i].lang)  sum+=Number(inp[i].value*_(inp[i].lang).value);
			else sum+=Number(inp[i].value);
		}
	}
	document.getElementsByTagName("h1")[0].getElementsByTagName("span")[0].innerHTML=sum+"$";
};