Question

Im using the following method to add up text boxes. I have tried changing multiple things and cant seem to multiply two text box values! essential I want 2 text box that values are multiplied and displayed in a third text box. I want this value to be fluid aka change when the number changes! I was using this code because i may be multiplying more then one thing but if this is too much of a hassle i will live with just multiplying two at a time

The code im using to add is

 <!--adding script #-->    
 <script>

$(document).ready(function(){
    calculateSum();

    //iterate through each textboxes and add keyup
    //handler to trigger sum event

    $(".txt").each(function() {

        $(this).keyup(function(){
            calculateSum();
        });
    });

});

function calculateSum() {

    var sum = 0;


    $("#sum").val(sum.toFixed(2));
    //iterate through each textboxes and add the values
    $(".txt").each(function() {


        //add only if the value is number
        if(!isNaN(this.value) && this.value.length!=0) {

            sum += parseFloat(this.value);
        }

    });
    //.toFixed() method will roundoff the final sum to 2 decimal places
    $("#sum").html(sum.toFixed(2));

      var total = document.getElementById("subtotal").value == "";
     var total = document.getElementById("subtotal").value = sum;
             }
    <!--END adding script #-->   

I tried setting the last line to

      var times1 = document.getElementById(subtotal);
      var times2 = document.getElementById(tax);
  var equal = times1.value * times2.value;

and then changing var total1 = document.getElementById(“total1”).value = sum9; to var total1 = document.getElementById(“total1”).value = equal;

The text boxes id are subtotal and tax the box im trying to update is total1.

Thanks alot!

Answer 1

On every keyup, instead of getting all values and adding them explicitly, it is better to deduct the previous value of the corresponding input and add the current updated value to sum..

Also, if subtotal is correctly calculated, then the multipication operation what ever you have done should work correctly..

Please find the following jsfiddle where the sum is calculated as explained above along with multiplying the tax..

http://jsfiddle.net/tgvrs_santhosh/77uxK/1/

Let me know if you still face the issue..