Calculations on Change dynamic events

Wappler General How To
#1

Where is the problem ? @ben @Teodor

<div class="form-group col">
   <label for="inp_valore_prezzo_lordo_articolo">Prezzo ivato</label>
      <input type="text" class="form-control" id="inp_valore_prezzo_lordo_articolo" name="valore_prezzo_lordo_articolo" aria-describedby="inp_valore_prezzo_lordo_articolo_help" dmx-on:change="modal_insert.serverconnectform1.inp_valore_prezzo_netto_articolo.setValue(value.toNumber() / (inp_percentuale_iva_articolo.value.toNumber() + 100.toNumber()))">
</div>

The calculation I want to do is this:
textinput 1 (total amount - ex: 12,20)
textinput 2 (tax - ex: 22%)
result = textinput 3 (total without tax - result 10,00)

I want set another input text value when data change in this text input. I speak of mathematical calculations with all numerical values or percentages.

Thank you

#2

Your current formula does: value/value2 +100 what should the formula do exactly? What are the exact math calculations you want to use there?
Do you want to substract the percentage from the value?

#3

Valute / ((value2/100)+1)

Example:
122 / ((22/100)+1)

#4

Do you want to substract the percentage from the value?

#5

Yes

#6

22%

#7

The formula for substacting the percentage from a value is:

value1 - (value1 * (value2/100))

Where value1 is the text input 1 (total value)
Value2 is the text input 2 (percentage)

Just recreate this formula with your inputs…

#8

sorry but this formula is not correct

#9

For example I have 12,20 total amount

Tax. 22%

Correct formula is:
12,20 / 1,22 = 10,00
Ok?

#10

My formula is exactly right :slight_smile:

120 - (120 * (22/100) =
120 - (120 * (0.22)) =
120 - (26.4) =
93.6

120-22% = 93.6

Simple maths for second grade.

#11

No.

If you add percentage to 93.6
93.6+22% = 114.19 and not 120
Ok?

#12

You told me you want to substract a given percentage from a value.
That is what my formula does. If it doesn’t work for you then explain a little better what you need to do?

You can even argue with the calculator if you like: https://www.google.com/search?client=firefox-b-ab&q=120-22%

#13

I want this math:

Value1 122,00
Value2 22%

122,00 / ((22/100)+1)
122,00 / (0,22+1)
122,00 / 1,22 = 100,00

Verify: 100,00+22%=122,00

How can I do in wappler ?

#14

I think this should work for subtracting VAT:

  <div class="form-group">
    <label for="input1">Price incl. VAT</label>
    <input type="text" class="form-control" id="input1" name="input1" aria-describedby="input1_help" dmx-on:change="input3.setValue(value.toNumber() / (input2.value.toNumber() + 100) * 100)">
  </div>
  <div class="form-group">
    <label for="input2">VAT Rate</label>
    <input type="text" class="form-control form-control-plaintext" id="input2" name="input2" value="22" aria-describedby="input1_help" readonly="true">
  </div>
  <div class="form-group">
    <label for="input3">Price excl. VAT</label>
    <input type="text" class="form-control" id="input3" name="input3" aria-describedby="input3_help" readonly="true">
  </div>
#15

Yes, exactly

#16

Well if you know the formula you want to use just add it and replace the values with your inputs.

#17

Teodor’s math is correct given the information . you are giving.

For example:

100+22%=122.00
122.00-22%=95.16

#18

it doens’t work
see this link: https://erp.decoresin.com/app/documenti/test-iva.html
thank you

result NaN

#19

That’s strange. It worked for me locally and I’ve just tested it on a website. I’m sure the calculations are correct. This is what I see:

image

#20

You are missing required includes from your page. It’s missing the formatter js include from your head tags.