make a input field required if radio is checked

Question

Can I somehow insert the required attribute into an input field only if a certain radio is checked?

I have an input field named \"ladder-meters\" that is not require

Answer 1

Easy to achieve with jQuery:

$('#ladder').change(function () {
    if($(this).is(':checked') {
        $('#ladder-meters').attr('required');
    } else {
        $('#ladder-meters').removeAttr('required');
    }
});

Answer 2

document.getElementById("ladder").addEventListener('change', function(){
    document.getElementById("ladder-meters").required = this.checked ;
})

Whenever the checkbox is clicked, the required attribute will be changed to match the checked attribute of the checkbox. To reverse this relationship, replace this.checked with !this.checked

This may need some adjustment to suit your specific project.

This will work with this checkbox:

<input type='checkbox' id='ladder' name='ladder' />

Answer 3

Tried F. Orvalho, didn't work for me, I had to use

$('#ladder').change(function () {
    if(this.checked) {
        $('#ladder-meters').prop('required', true);
    } else {
        $('#ladder-meters').prop('required', false);
    }
});

It could be usefull. Thx to F. Orvalho for the structure