Calculate field change background dynamically

Hello,

I would like to ask how I can dynamically change the background of a calculated field with a button?

I have tried the following, but it does not work.

• my calculated field is number 4
• in my button under OnClick event I put the following:
  getField(4).jQueryRef().removeClass(‘red green orange’).addClass(‘green’);

My Button is also for the calculate for the form.

in my CSS is the following:

#fbuilder .red .cff-calculated-field input{background-color:#fccbc8 !important;}
#fbuilder .green .cff-calculated-field input{background-color:#90ee90 !important;}
#fbuilder .orange .cff-calculated-field input{background-color:#f6d77a !important;}

Where is the error?

Thank you.