Change image opacity when select an option from a form

April 12, 2023

How can I make when I select the option that has value 1(Mastercard) the image with id Master change the opacity to 1? And put it in a function that works for both 4 values, each on with his own id? The default image I want it to be 0.3 and when selected one of the option the image has the opacity 1.

.itemForm2 {
  width: 100%;
  position: relative;
  margin-bottom: 18px;
  margin-top: 10px;
  display: flex;
  flex-direction: row;
}

.escolhaCartao {
  display: flex;
  flex-direction: row;
  width: 218px!important;
  gap: 10px;
}

@media(min-width:768px) {
  .escolhaCartao {
    width: 258px!important;
    height: 34.32px;
    gap: 5px;
  }
  .lineFormCartao {
    display: flex;
    flex-direction: row;
    justify-content: inherit;
    gap: 16px;
  }
  .escolhaCartao img {
    opacity: .3;
  }
}

<div class="lineForm lineFormCartao">
  <div class="itemForm">
    <select id="OpcoesCartao" name="OpcoesCartao">
      <option value="1">Mastercard</option>
      <option value="2">Visa</option>
      <option value="3">Elo</option>
      <option value="4">Amex</option>
    </select>
  </div>
  <div class="itemForm2 escolhaCartao">
    <img id="master" src="images/master.png" alt="Logo cartão Mastercard">
    <img id="visa" src="images/visa.png" alt="Logo cartão Visa">
    <img id="elo" src="images/elo.png" alt="Logo cartão Elo">
    <img id="amex" src="images/amex.png" alt="Logo cartão Amex">
  </div>
</div>

>Solution :

You can do it like this. This works in most browsers. Firefox should support it soon (https://caniuse.com/?search=has)

.itemForm2 {
    width: 100%;
    position: relative;
    margin-bottom: 18px;
    margin-top: 10px;
    display: flex;
    flex-direction: row;
}

.escolhaCartao {
    display: flex;
    flex-direction: row;
    width: 218px!important;
    gap: 10px;
}

.lineForm:has( option[value="1"]:checked ) #master {
  opacity: 1;
}
.lineForm:has( option[value="2"]:checked ) #visa {
  opacity: 1;
}
.lineForm:has( option[value="3"]:checked ) #elo {
  opacity: 1;
}
.lineForm:has( option[value="4"]:checked ) #amex {
  opacity: 1;
}


    .escolhaCartao {
        width: 258px!important;
        height: 34.32px;
        gap: 5px;
    }

    .lineFormCartao {
        display: flex;
        flex-direction: row;
        justify-content: inherit;
        gap: 16px;
    }
    .escolhaCartao img {
        opacity: .3;
    }

<div class="lineForm lineFormCartao">
        <div class="itemForm">
             <select id="OpcoesCartao" name="OpcoesCartao">
                 <option value="1">Mastercard</option>
                 <option value="2">Visa</option>
                 <option value="3">Elo</option>
                 <option value="4">Amex</option>
             </select>
        </div>
        <div class="itemForm2 escolhaCartao">
            <img id="master" src="images/master.png" alt="Logo cartão Mastercard">
            <img id="visa" src="images/visa.png" alt="Logo cartão Visa">
            <img id="elo" src="images/elo.png" alt="Logo cartão Elo">
            <img id="amex" src="images/amex.png" alt="Logo cartão Amex">
       </div>
</div>