var amount, apr, n, payment, npy, tablebuilt=false; function calculate(){ var d=document.f; amount=d.amount.value; apr=d.apr.value; n=d.n.value; npy=d.npy.value; if( (amount!='') && (n!='') && (apr!='') && (npy!='') ){ tmp=Math.pow((1+(apr/100/npy)), (n*npy)); payment=(amount*tmp*(apr/100/npy))/(tmp-1); if((!isNaN(payment))&&(payment!=Number.POSITIVE_INFINITY)&&(payment!=Number.NEGATIVE_INFINITY)){ d.payment.value=round(payment); //d.totpaid.value=round(payment*n*npy); //d.intpaid.value=round((payment*n*npy)-amount); }else alert('Error:\nOne or more fields contain data\nwhich cannot be used in the\ncalculation.'); }else alert('Error:\nYou did not provide enough data.'); } function round(val){ tmp=Math.round(val*100)/100+''; if(tmp.indexOf('.')==-1)tmp+='.00'; else if(tmp.length-tmp.indexOf('.')==2)tmp+='0'; return tmp; } function resetall(){ var d=document.f; d.amount.value=''; d.apr.value=''; d.n.value=''; d.npy.value=12; d.payment.value=''; //d.totpaid.value=''; //d.intpaid.value=''; d.amount.focus(); } function buildtable(){ tablebuilt=true; txt='Payment Schedule
'; txt+='

'; txt+=''; txt+=''; amount=eval(amount); for(i=1;i<=n*npy;i++){ tbldata=''+tbldata+i+':'+tbldata+round(payment)+''+tbldata+round(interest)+''+tbldata+round(principle)+''+tbldata+round(amount)+''; } txt+='
Payment
Number		Payment
Amount		InterestPrincipleBalance
'; interest=amount*apr/npy/100; amount+=interest; principle=payment-interest; amount-=payment; txt+='


'; var psch=window.open('', 'viewsch' ,'top=0,left=0,toolbar=no,scrollbars=yes,resizable=yes,width=500,height=450,menubar=no,status=no'); psch.document.write(txt); } window.onload=function(){ document.f.amount.focus(); }