Here is my problem: Compute the Monthly Payment for a Loan Write a Javascript program that computes monthly interest payments for a home or car loan. You must use text boxes to get the input from the user. Inputs = Loan amount (principal) r = Interest rate in percent n = Number of years (duration of loan) Output:M = Monthly payment Here is the formula: M=Pr / 1200.01 – (1.0 + r / 1200.0) –12n Use parseFloat to convert the inputs into numbers. Use a function (with a name like computeMonthlyPayment) to compute the monthly payment M. Use the following JavaScript formula for computing the monthly payment: M = (P * r / 1200.0) / (1 - Math.pow(1.0 + r / 1200.0, -12.0 * n)); -------------------------------------------------------------------------- Here is the code I've got so far <html> <head> <title>JavaScript Loan Example</title> <script type="text/javascript"> function compute(){ rate =document.frmcalc.txtRate.value; principal=document.frmcalc.txtPrince.value; year=document.frmcalc.txtYears.value; </script> </head> <body> <form name="frmcalc"> <p>Type your rate here:</p> <input type="text" name="txtRate" size="7" value="" /> <p>Type your principal here:</p> <input type="text" name="txtPrince" size="7" value="" /> <p>Type the duration of your loan in years:<p> <input type="text" name="txtYears" size="7" value="" /> </br> <input type="button" value="Click to calculate your loan" onclick="compute();"> <P> Your loan payment is <input type="text" size="7" name="res" value=""> </form> </body> </html> -------------------------------------------------------------------------- I've kind of been doing it backwards, going back and doing some things that I know how to set up while leaving parts blank My teacher kind of sucks I especially don't understand how to "parse" the numbers Any help is appreciated

* Use parseFloat to convert the inputs into numbers. Where you have: rate =document.frmcalc.txtRate.value; You should have: rate = parseFloat(document.frmcalc.txtRate.value); * Use a function (with a name like computeMonthlyPayment) to compute the monthly payment M. You already did this. * Use the following JavaScript formula for computing the monthly payment: M = (P * r / 1200.0) / (1 - Math.pow(1.0 + r / 1200.0, -12.0 * n)); Now you just need to replace his variables (M, P, r, n) with yours. P = principal r = rate n = year So you end up with: M = (principal * rate / 1200.0) / (1 - Math.pow(1.0 + rate / 1200.0, -12.0 * year)); You'd want to end your function with an alert or something to return the monthly payment: alert(M); Edit: Instead of alert(M); you want it in a text box? So you do: document.frmcalc.res.value = M;

hmmm ok I think I'm getting somewhere here is what I've got now in the function but I am still getting errors function compute(){ rate = parseFloat(document.frmcalc.txtRate.value); principal=parseFloat(document.frmcalc.txtPrince.value); year=parseFLoat(document.frmcalc.txtYears.value); M = (principal * rate / 1200.0) / (1 - Math.pow(1.0 + rate / 1200.0, -12.0 * year)); }

Okay, a few problems in your code like random spaces and improper casing: principal=parseFloat(document.frmcalc.txtPrince.va lue); year=parseFLoat(document.frmcalc.txtYears.value); The following works, I put the alert('test') in to see where it was breaking. You'll want to remove those. You'll likely want to use a function to set the decimal point (precision) to two. You can learn more about that here: http://www.mredkj.com/javascript/nfbasic2.html Code: <html> <head> <title>JavaScript Loan Example</title> <script type="text/javascript"> function computeLoan(){ alert('test'); rate = parseFloat(document.frmcalc.txtRate.value); principal=parseFloat(document.frmcalc.txtPrince.value); year=parseFloat(document.frmcalc.txtYears.value); alert('test'); M = (principal * rate / 1200.0) / (1 - Math.pow(1.0 + rate / 1200.0, -12.0 * year)); alert(M); document.frmcalc.res.value = M; } </script> </head> <body> <form name="frmcalc"> <p>Type your rate here:</p> <input type="text" name="txtRate" size="7" value="" /> <p>Type your principal here:</p> <input type="text" name="txtPrince" size="7" value="" /> <p>Type the duration of your loan in years:<p> <input type="text" name="txtYears" size="7" value="" /> </br> <input type="button" value="Click to calculate your loan" onclick="computeLoan();"> <P> Your loan payment is <input type="text" size="7" name="res" value=""> </form> </body> </html>