<label class="checkbox-inline">
<input type="checkbox" id="certificate" value="true"> Да
</label>
<label class="input_text" for="number_certificate">Номер сертификата</label>
<input name="number_certificate" type="text" class="form-control input_text" id="number_certificate" placeholder="Номер сертификата">
var myCheckbox = document.querySelector('#certificate')
var myInput = document.querySelector('#number_certificate')
myCheckbox.addEventListener('change', function(){
myInput.disabled = !myCheckbox.checked
})