Multiple similar event handlers for input validation
You can use functions for those validations:

var validations = {
    '.js-mandatory-notnull': function(val) {
        return val.length &gt; 0;
    },
    '.js-mandatory-2words': function(val) {
        return val.match(/^[A-Za-zÀ-ú]+ [A-Za-zÀ-ú]+/i);
    },
    '.js-mandatory-numb': function(val) {
        return val.match(/^(?=.*\d)\d*[\.\,]?\d*$/);
    }
}


And then install those via a loop:

$.each(validations, function(selector, validate) {
    $(document).on('keyup change focusout', selector, function(e){
        validateInput(e, $(this), validate(this.value));
    });
});