calculate multiple input value in javascript

Question

I have 5 input fields (range sliders) and I'm trying to return a result when any of the input values changes. The problem is "value4" is used 2 times in the equation and this is causing the problem. If I change "value4" my result does not change.

      function output(){
      var value1 = document.getElementById('NumberOfEmployees_input').value;
      var value2 = document.getElementById('AverageSalary_input').value;
      var value3 = document.getElementById('AverageTime_input').value;
      var value4 = document.getElementById('WorkdaysWeek_input').value;
      var value5 = document.getElementById('AccountingHours_input').value;

      document.getElementById('saving').innerHTML =
          (((parseInt(value1) * parseInt(value2))/(parseInt(value4) * parseInt(1920))) * (parseInt(value3) * parseInt(value4) * parseInt(48)))
          + (parseInt(value5) * parseInt(13500)) - parseInt(183600);
  }

Can anybody give me a hint? Thank you!

value4 cancels out in your equation. You can opt to use it 0 times. Save the case where value4 = 0. — TrebledJ
– TrebledJ, Commented Nov 14, 2018 at 10:25

cusmar · Accepted Answer · 2018-11-14 10:35:11Z

2

Your equation can be simplified, you added too many brackets (I removed the parseInt() function to make it more readable).

It is equivalent to:

value4 is canceled:

You may have made an error in your equation.

answered Nov 14, 2018 at 10:35

cusmar

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2 Comments

TrebledJ Over a year ago

You got there faster than me, with tex too. :P Nice.

Ali Seivani Over a year ago

@cusmar you are right. I made an error in my equation. Thank you!

Ahmad · Accepted Answer · 2018-11-14 11:39:43Z

1

The code is very difficult to read. I suggest simplifying the code by first, shortening the variable names. Then apply parseInt at an early stage to reduce clutter afterwards. Plus, there is no need to parseInt(123) since 123 is already Integer.

function output(){
  var v1 = parseInt(document.getElementById('NumberOfEmployees_input').value);
  var v2 = parseInt(document.getElementById('AverageSalary_input').value);
  var v3 = parseInt(document.getElementById('AverageTime_input').value);
  var v4 = parseInt(document.getElementById('WorkdaysWeek_input').value);
  var v5 = parseInt(document.getElementById('AccountingHours_input').value);

  var n = v1 * v2;  // nominator
  var d = v4 * 1920 * v3 * v4 * 48;  // denominator

  document.getElementById('saving').innerHTML = (n/d) + (v5 * 13500) - 183600;

}

edited Nov 14, 2018 at 11:39

answered Nov 14, 2018 at 10:36

Ahmad

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1 Comment

TrebledJ Over a year ago

I agree the parentheses are a mess. Moreover, "the code is difficult to read" speaks for itself by confusing your numerators and denominators. : )

TrebledJ · Accepted Answer · 2018-11-14 11:43:51Z

1

Here is your equation

(
 (
  (parseInt(value1) * parseInt(value2))
   /
  (parseInt(value4) * parseInt(1920))
 ) *
 (parseInt(value3) * parseInt(value4) * parseInt(48))
)
+ (parseInt(value5) * parseInt(13500))
- parseInt(183600);

   v1 • v2
(-----------  • v3 • v4 • 48) + (v5 • 13500) - 183600
  v4 • 1920

//  valueN has been substituted with vN

By observation, v4 cancels out.

This reduces your chain of math to

( (parseInt(value1)*parseInt(value2)*parseInt(value3)*48) / 1920 )
    + (parseInt(value5) * 13500)
    - 183600;

Note that originally, v4 = 0 would fail. This may or may not be intended.

To make your code more readable you can separate the numerator and denominator as so

n = parseInt(value1) * parseInt(value2) * parseInt(value3) * 48
document.getElementById('saving').innerHTML = (n/1920) + (v5 * 13500) - 183600;

While this might not answer your question of using 2 input values, this provides a workaround in your situation. You didn't seem to realise this when you posted your question. Perhaps you misplaced a bracket or made an error in your calculations?

edited Nov 14, 2018 at 11:43

answered Nov 14, 2018 at 10:36

TrebledJ

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1 Comment

Ali Seivani Over a year ago

I made an error in simplifying my equation. Your answer is very useful and helped me refine my mess. Thank you!

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