var validchars = "0123456789.";

function isvalid(c) { 
   if (validchars.indexOf(c) != -1) return true;
   return false;
}

function value_check(fform) { 
	var emsg = "\半\角\で\入\力\し\て\下\さ\い\。\n\入\力\を\消\去\し\ま\す\。";
	var emsg2 = "\正\し\い\数\値\を\入\力\し\て\下\さ\い\。";
	var tstr = fform.value;
	var counter = 0;

	for (i=0;i<tstr.length;i++) {
		if(tstr.charAt(i) == '.'){
			counter++;
			if(counter > 1){
				alert(emsg2);
				fform.value = "";
				fform.focus();
				return false; 
			}
								
		}
		if ( isvalid(tstr.charAt(i)) ) continue;
         	alert(emsg);
		fform.value="";
		fform.focus();
         	return false; }
}

/*　
Main Function 
*/
function calc(){
	var emsg_n="\必\須\項\目\が\未\入\力\で\す\。";
	var emsg_n2="\正\し\い\数\値\を\入\力\し\て\下\さ\い\。";
	var ttl=Number(document.cal_ldl.ttl.value);
	var hdl=Number(document.cal_ldl.hdl.value);
	var tg=Number(document.cal_ldl.tg.value);
	var ldl;
	var buf= "";

	if(ttl == ""){
		alert(emsg_n);
		ttl.focus();
		}
	if(ttl < 99 || ttl > 500){
		alert(emsg_n2);
		ttl.focus();
		}
	if(hdl == ""){
		alert(emsg_n);
		hdl.focus();
		}
	if(hdl < 20 || hdl > 150){
		alert(emsg_n2);
		hdl.focus();
		}
	if(tg == ""){
		alert(emsg_n);
		tg.focus();
		}
	if(tg < 20 || tg > 399){
		alert(emsg_n2);
		tg.focus();
		}
	
	//LDL Calculation
	ldl =  ttl - hdl - tg / 5;
	document.cal_ldl.ldl.value = ldl;
	

}