I have script
$(document).ready(function(){
var phoneInput = $('.custom-options').val(372);
var inputCart = $('.wc-variation-selection-needed');
inputCart.attr('disabled','disabled');
phoneInput.keyup(function() {
if (!phoneInput.val().match(/^372\d{8}$/)) {
inputCart.attr('disabled','disabled');
} else {
inputCart.removeAttr('disabled');
}
});
});
this work, but only once, if i click the button and send form, inputCart will be still enable.