How do I programmatically set the value of a select box element using JavaScript?

Question

I have the following HTML element:

Annual Leave&l

Answer 1

If you are using jQuery you can also do this:

$('#leaveCode').val('14');

This will select the with the value of 14.

---

With plain Javascript, this can also be achieved with two Document methods:

• With document.querySelector, you can select an element based on a CSS selector:

  document.querySelector('#leaveCode').value = '14'
  

• Using the more established approach with document.getElementById(), that will, as the name of the function implies, let you select an element based on its id:

  document.getElementById('leaveCode').value = '14'
  

You can run the below code snipped to see these methods and the jQuery function in action:

const jQueryFunction = () => {
  
  $('#leaveCode').val('14'); 
  
}

const querySelectorFunction = () => {
  
  document.querySelector('#leaveCode').value = '14' 
  
}

const getElementByIdFunction = () => {
  
  document.getElementById('leaveCode').value='14' 
  
}

input {
  display:block;
  margin: 10px;
  padding: 10px
}

  Annual Leave
  Medical Leave
  Long Service
  Leave Without Pay