如何将单选按钮值设置为选中或未选中的情况

Question

<input type="radio" name="imgsel"  value="" checked />

My requirement is: This radio button by default checked then value of this button is 'present'. When this button is unchecked, then value this button is 'absent'. how can i do this?

please, help me. Thanks in advance.

Answer 1

 function valChange(element) { if (element.checked) { alert("present"); } else { alert("absent"); } }

 <input id="button" type="checkbox" name="imgsel" onchange="valChange(this)" value="" checked />

Answer 2

The following example replaces the value of the checkbox when clicked. First the click event must be bound to the checkbox. The EventHandler checks whether the box has already been checked. If not, it checks it and sets the value in the checkbox. And if it has not been checked, the other way round.

 let i = document.querySelector('input'); i.addEventListener('click', (ev) => { let el = ev.target; if (el.getAttribute('checked') === null) { el.setAttribute('checked', true); el.value = "present" } else { el.removeAttribute('checked'); el.value = "absent" } let checkValue = document.querySelector('input').value alert(checkValue) })

 <input type="radio" name="imgsel" value="" checked />