Math Related : Credit Card Debt Calculator / The JavaScript Source

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General

This script will calculate how long it will take to pay off credit card debt. It will also calculate the total interest that will be paid over that same period.

Notes

Created by: Chris Crenshaw
Web Site: http://www.creditcarddebtnegotiation.org/
Posted: May 30, 2008

Source Code

Paste this source code into the designated areas.

External file

Paste this code into an external JavaScript file named: creditCardDebtCalculator.js

/* This script and many more are available free online at
The JavaScript Source!! http://javascript.internet.com
Created by: Chris Crenshaw | http://www.creditcarddebtnegotiation.org/ */

// validation function
function isValid(entry, a, b) {
  if (isNaN(entry.value) || (entry.value==null) || (entry.value=="") || (entry.value < a) || (entry.value > b)) {
  alert("Invalid entry. Your min payment should be between " + a + " and " + b + ".")
	entry.focus()
  entry.select()
	return false
  }
	return true
}

// clear results fields when input values changed
function clearCalcs(form) {
	form.num_months.value = ""
	form.total_pay.value = ""
	form.total_int.value = ""
}

function calculate(form) {
// send entries to validation function
// exit if not valid
	if (!isValid(form.balance, 0, 100000)) {  
		return false
	} else if (!isValid(form.interest, 0, 30)) {  
		return false
	} else {         
		var init_bal = eval(form.balance.value);
	}
	if (!isValid(form.mnth_pay, init_bal*.02, init_bal)) {
		return false
  } else {
	// variables used in calculation
	var cur_bal = init_bal;		// used in loop
	var interest = eval(form.interest.value/100);
	var mnth_pay = eval(form.mnth_pay.value);
	var fin_chg = 0;			// finance charge
	var num_mnths = 0;
	var tot_int = 0;
  }
	
  while (cur_bal > 0) {
    fin_chg = cur_bal*interest/12;
    cur_bal = cur_bal - mnth_pay + fin_chg;
    num_mnths++;
			if (num_mnths > 300) {
      	alert("We are interrupting this process to prevent a hang which may result with a very high balance, high interest rate and low monthly payment.\n\nTry entering a higher monthly payment amount." )
				form.mnth_pay.focus()
				form.mnth_pay.select()
				return
      }
    tot_int += fin_chg;
  }
	
// display result
	form.num_months.value = num_mnths;
	form.total_pay.value ="$" + round(init_bal + tot_int);
	form.total_int.value ="$" + round(tot_int);
   }

// round to 2 decimal places
function round(x) {
	return Math.round(x*100)/100;
}

Head

Paste this code into the HEAD section of your HTML document.


<script type="text/javascript" src="creditCardDebtCalculator.js"></script>

Body

Paste this code into the BODY section of your HTML document


<div style="width: 400px;">
<form>
<table border="0" cellspacing="0" cellpadding="0" style="width:80%">
<tbody>
<tr>
<td>Total Credit Card Debt:</td>
<td style="width:150px"><input name="balance" size="12" type="text" style="width:150px"></td>
</tr>
<tr style="background:#eef6f9">
<td>Interest Rate (Annual Percentage):</td>
<td style="width:150px"><input name="interest" size="12" type="text" style="width:150px"></td>
</tr>
<tr>
<td>Current Monthly Payment:</td>
<td style="width:150px"><input name="mnth_pay" size="12" type="text" style="width:150px"></td>
</tr>

<tr>
<td colspan="2" style="text-align:center;padding-top:10px">
<input onclick="calculate(this.form)" type="button" value="Calculate" style="width:220px"> 
<input type="reset" style="width:220px">
</td>
</tr>
<tr>
<td style="padding-top:20px">Months It Will Take To Be Debt Free:</td>
<td style="padding-top:20px"><input name="num_months" size="12" type="text" style="width:150px"></td>
</tr>
<tr style="background:#eef6f9">
<td>Total Amount Payed To Lender:</td>
<td style="width:150px"><input name="total_pay" size="12" type="text" style="width:150px"></td>
</tr>
<tr>

<td>Total Interest Paid To Lender:</td>
<td style="width:150px"><input name="total_int" size="12" type="text" style="width:150px"></td>
</tr>
</tbody>
</table>
</form>
</div>

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Head

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User Comments

1. From: sharat
might be helpfull
06/01/2008 23:58:55

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Total Credit Card Debt:
Interest Rate (Annual Percentage):
Current Monthly Payment:

Months It Will Take To Be Debt Free:
Total Amount Payed To Lender:
Total Interest Paid To Lender:

Navigation Menu

Internet.commerce

Internet.com

Developer Channel

Great Sites

Promotions

General

Notes

Source Code

External file

Head

Body

User Comments

1. From: sharatmight be helpfull06/01/2008 23:58:55

Whitepapers and eBooks

Webcasts

Downloads and eKits

Tutorials and Demos

1. From: sharat
might be helpfull
06/01/2008 23:58:55