How to calculate EMI using JQuery

Formula: EMI = (P * r/12) * [ (1+r/12)^n] / [ (1+r/12)^n-1]

Where,
P = Outstanding Principle
r = Interest Rate
n = Tenure (in months)

Following is the JS Code to calculate EMI

<script type="text/javascript">
function calculateEMI(obj) {                                               
 // Formula: 
 // EMI = (P * R/12) * [ (1+R/12)^N] / [ (1+R/12)^N-1]                               
                
 // isNaN(isNotaNumber): Check whether the value is Number or Not                
    if (!isNaN(obj.value) && obj.value.length !== 0) {
                    
    var emi = 0;
    var P = 0;
    var n = 1;
    var r = 0;                                       
                    
   // parseFloat: This function parses a string 
  // and returns a floating point number
    if($("#outstanding_principle").val() !== "")
       P = parseFloat($("#outstanding_principle").val());
                   
                        
    if ($("#interest_rate").val() !== "") 
      r = parseFloat(parseFloat($("#interest_rate").val()) / 100);

    if ($("#tenure").val() !== "")
        n = parseFloat($("#tenure").val());
                    
    // Math.pow(): This function returns the value of x to power of y 
    // Example: (5^2)
                    
    // toFixed: Convert a number into string by keeping desired decimals                   
                    
    if (P !== 0 && n !== 0 && r !== 0)
    emi = parseFloat((P * r / 12) * [Math.pow((1 + r / 12), n)] / [Math.pow((1 + r / 12), n) - 1]);
              
    $("#emi").val(emi.toFixed(2));
                
  }
}
</script>

And Following is the HTML code

<table>
   <tr>
     <th>Outstanding Principle</th>
     <th>Interest Rate (%)</th>
     <th>Tenure (in Months)</th>
     <th>EMI</th>
   </tr>
   <tr>
     <td>
       <input type="text" id="outstanding_principle" onchange="calculateEMI(this);">
     </td>
     <td>
       <input type="text" id="interest_rate" onchange="calculateEMI(this);">
     </td>
     <td>
       <input type="text" id="tenure" onchange="calculateEMI(this);">
     </td>
     <td>
       <input type="text" readonly="true" id="emi">
     </td>
 </tr>                
</table>

Demo