Getting value from input field vanilla javascript-CodePudding

Im trying to get the value of my input field with vanilla javascript to create a tip calculator.

For some reason, the value returns but as empty. I have tried innerText, innetHTML, value, and it doesn't work.

Can someone point me what is my mistake here?

const calculateTipBtn = document.getElementById('calculate');
const totalBill = document.getElementById('totalBill').value;
const resetBtn = document.getElementById('reset');

calculateTipBtn.addEventListener('click', () => {

  if (totalBill.value === '') {
    console.log('Value can\'t be empty')
  } else {
    alert('there is something')
    console.log(totalBill)
  }
  console.log(totalBill)
})

resetBtn.addEventListener('click', () => {
  window.location.reload()
})

<div id="wrapper">
  <header>Vanilla Tip Calculator</header>

  <div >
    <label for="totalBill">Enter Total bill</label>
    <input type="text" name="total" id="totalBill">
    <label for="tipPercentage"> How much tip are you feeling?</label>
    <input type="checkbox" name="tip" value="15"><span>15%</span>
    <input type="checkbox" name="tip" value="20"><span>20%</span>
    <input type="checkbox" name="tip" value="30"><span>30%</span>
    <br>
    <button id="calculate">Calculate!</button>
    <button id="reset">Reset</button>
  </div>

  <div ></div>
</div>

CodePudding user response：

All you have to do is to push below line inside the addEventListener. You are caputuring or taking value at the start of the script, till then the input is empty and then the value will be empty. So I think you want to take a value when you enter something in the input and when you click calculate button. i.e. inside the event listener.

calculateTipBtn.addEventListener('click', () => {
  const totalBill = document.getElementById('totalBill').value; // THIS
  if (totalBill.value === '') {
    console.log("Value can't be empty");
  } else {
    alert('there is something');
    console.log(totalBill);
  }
  console.log(totalBill);
});

const calculateTipBtn = document.getElementById('calculate');
const resetBtn = document.getElementById('reset');
const totalBill = document.getElementById('totalBill');

calculateTipBtn.addEventListener('click', () => {
  const totalBillValue = totalBill.value;
  if (totalBill.value === '') {
    console.log("Value can't be empty");
  } else {
    alert('there is something');
    console.log(totalBillValue);
  }
});

resetBtn.addEventListener('click', () => {
  window.location.reload();
});

<div id="wrapper">
  <header>Vanilla Tip Calculator</header>

  <div >
    <label for="totalBill">Enter Total bill</label>
    <input type="text" name="total" id="totalBill" />
    <label for="tipPercentage"> How much tip are you feeling?</label>
    <input type="checkbox" name="tip" value="15" /><span>15%</span>
    <input type="checkbox" name="tip" value="20" /><span>20%</span>
    <input type="checkbox" name="tip" value="30" /><span>30%</span>
    <br />
    <button id="calculate">Calculate!</button>
    <button id="reset">Reset</button>
  </div>

  <div ></div>
</div>

CodePudding user response：

I think you need to move

const totalBill = document.getElementById('totalBill').value;

Inside the on click event, otherwise you will read the empty value when the page loads.

CodePudding user response：

You initialize totalBill variable on script load and before you click on the calculate button. move totalBill inside onClick

const calculateTipBtn = document.getElementById('calculate');
const resetBtn = document.getElementById('reset');

calculateTipBtn.addEventListener('click', () => {
  const totalBill = document.getElementById('totalBill').value;
  if (totalBill === '') {
    console.log('Value can\'t be empty')
  } else {
    alert('there is something')
    console.log(totalBill)
  }
})

resetBtn.addEventListener('click', () => {
  window.location.reload()
})