perform an action on checkbox checked or unchecked event on html form

Question

I have a checkbox on a form which is unchecked by default as usual. now I want to perform two separated actions on checked and unchecked state of this checkbox.

this

Answer 1

We can do this using JavaScript, no need of jQuery. Just pass the changed element and let JavaScript handle it.

HTML

    syn

JS

function doalert(checkboxElem) {
  if (checkboxElem.checked) {
    alert ("hi");
  } else {
    alert ("bye");
  }
}

Demo Here