CODEWITHSUNDEEP
javascripthtml
Henry N.
Henry N.

Reputation: 15

How to swap options between two <select> list

I'm new to Javascript, and I want to swap these two options when the exchange button is clicked Page

enter image description here

HTML

<div class="form-group col-4">
    <button type="button" class="btn bg-dark text-white" id="exchange" style="margin-top: 23px; margin-left: 10px;"> 
          <i class="fa fa-exchange" aria-hidden="true"></i>
    </button>
</div>

Javascript

function swap() {
  let inp = document.getElementById("inputCurrency").value;
  let out = document.getElementById("outputCurrency").value;
  document.getElementById("inputCurrency").value = out;
  document.getElementById("outputCurrency").value = inp;
}

let amountInput = document.getElementById("amount");

let inputCurrency = document.getElementById("inputCurrency");
let outputCurrency = document.getElementById("outputCurrency");

let convertButton = document.getElementById('convertButton');
convertButton.addEventListener("click",convertCurrency);

let exchangeButton = document.getElementById("exchange");
exchangeButton.addEventListener("click",swap());

Upvotes: 0

Views: 201

Answers (2)

Hien Nguyen
Hien Nguyen

Reputation: 18975

You need remove function call in addEventListener, it contains only function name

exchangeButton.addEventListener("click",swap);


function swap() {
  let inp = document.getElementById("inputCurrency").value;
  let out = document.getElementById("outputCurrency").value;
  document.getElementById("inputCurrency").value = out;
  document.getElementById("outputCurrency").value = inp;
}

let amountInput = document.getElementById("amount");

let inputCurrency = document.getElementById("inputCurrency");
let outputCurrency = document.getElementById("outputCurrency");

let convertButton = document.getElementById('convertButton');
//convertButton.addEventListener("click",convertCurrency);

let exchangeButton = document.getElementById("exchange");
exchangeButton.addEventListener("click",swap);
<select id="inputCurrency">
<option value="1">USD</option>
<option value="2">KRW</option>
</select>
<select id="outputCurrency">
<option value="1">USD</option>
<option value="2">KRW</option>
</select>
<input type="text" id="amount"/>
<div class="form-group col-4">
    <button type="button" class="btn bg-dark text-white" id="exchange" style="margin-top: 23px; margin-left: 10px;"> Exchange
          <i class="fa fa-exchange" aria-hidden="true"></i>
    </button>
</div>
<button id="convertButton">Convert</button>

Upvotes: 0

zmag
zmag

Reputation: 8241

addEventListener needs a function for second parameter. Add a callback function that calls swap() function.

exchangeButton.addEventListener("click", e => swap());

Upvotes: 0

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